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The Beckmann rearrangement of ketoximes to their corresponding amides, using a Brønsted acid-mediated fragmentation and migration sequence, has found wide-spread industrial application. We postulated that the development of a methodology to access ylideneamino sulfates using tributylsulfoammonium betaine (TBSAB) would afford isolable Beckmann-type intermediates and competent partners for subsequent rearrangement cascades. The ylideneamino sulfates generated, isolated as their tributylammonium salts, are sufficiently activated to undergo Beckmann rearrangement without additional reagent activation. The generation of sulfuric acid in situ from the ylideneamino sulfate giving rise to a routine Beckmann rearrangement and additional amide bond cleavage to the corresponding aniline was detrimental to reaction success. The screening of bases revealed inexpensive sodium bicarbonate to be an effective additive to prevent classic Brønsted acid-mediated fragmentation and achieve optimal conversions of up to 99%. [ABSTRACT FROM AUTHOR]

The C(sp2)-aryl sulfonate functional group is found in bioactive molecules, but their synthesis can involve extreme temperatures (>190 °C or flash vacuum pyrolysis) and strongly acidic reaction conditions. Inspired by the 1917 Tyrer industrial process for a sulfa dye that involved an aniline N(sp2)-SO3 intermediate en route to a C(sp2)-SO3 rearranged product, we investigated tributylsulfoammonium betaine (TBSAB) as a milder N-sulfamation to C-sulfonate relay reagent. Initial investigations of a stepwise route involving TBSAB on selected anilines at room temperature enabled the isolation of N(sp2)-sulfamate. Subsequent thermal rearrangement demonstrated the intermediary of a sulfamate en route to the sulfonate; however, it was low-yielding. Investigation of the N-sulfamate to C--sulfonate mechanism through control experiments with variation at the heteroatom positions and kinetic isotope experiments (KIEH/D) confirmed the formation of a key N(sp2)-SO3 intermediate and further confirmed an intermolecular mechanism. Furthermore, compounds without an accessible nitrogen (or oxygen) lone pair did not undergo sulfamation- (or sulfation) -to-sulfonation under these conditions. A one-pot sulfamation and thermal sulfonation reaction was ultimately developed and explored on a range of aniline and heterocyclic scaffolds with high conversions, including N(sp2)-sulfamates (O(sp2)-sulfates) and C(sp2)-sulfonates, in up to 99 and 80% (and 88% for a phenolic example) isolated yield, respectively. Encouragingly, the ability to modulate the ortho-para selectivity of the products obtained was observed under thermal control. A sulfonated analog of the intravenous anesthetic propofol was isolated (88% yield), demonstrating a proof-of-concept modification of a licensed drug alongside a range of nitrogen- and sulfur-containing heterocyclic fragments used in drug discovery. [ABSTRACT FROM AUTHOR]

Holocellulose nanofibrils, as a two-component biomass nanomaterial, exhibit many advantages in surface/interface engineering fields, and show a broader prospect in the preparation of high-performance functional materials. However, there is a lack of research in this newly emerging material from the perspective of raw material selection. Herein, holocellulose derived from bamboo, pine, and eucalyptus are chosen to prepare sulfated holocellulose nanofibrils (SHCNFs) through sulfation and mechanical defibrillation. The sulfation and disintegration into SHCNFs are governed not only by the amount of hemicellulose, but also by the fiber morphology. The properties of SHCNFs largely depends on the plant species. Compared with the other two raw materials, bamboo holocellulose fibers have higher reaction accessibility and facile defibrillation property. The resulting bamboo SHCNF films exhibites excellent mechanical performance (tensile strength, 201 MPa; Young's modulus, 5.7 GPa). Moreover, the bamboo SHCNFs suspension shows good dispersibility. Therefore, it has more advantages in the preparation of multifunctional composite materials. [ABSTRACT FROM AUTHOR]

We used to consider native cellulose to be composed of microfibrils continuously crystalline along the chain direction with constant lateral dimension. To sulfate the surface of cellulose microfibrils, we activated cotton fibers by pre-swelling in water or DMF followed by immersion in an excess amount of sulfamic acid in dimethylformamide (DMF) in heterogeneous conditions. The degree of sulfation was followed by elemental analysis and conductometric titration, while the structural changes associated with the sulfation and the homogenization were investigated by infrared spectroscopy, solid-state NMR, and X-ray diffraction. The initial sulfation of the cellulose surface was well described as a first order reaction with a kinetic constant of 2 × 10 - 3 s - 1 at 80 °C using 3.6% sulfamic, indicating that about half of the available hydroxy groups were sulfated within the first 5 min. A water pre-swelling step, followed by solvent exchange with DMF, increased the amount of available hydroxy groups by up to a factor of two. At long reaction times, there was a gradual increase in the degree of sulfation beyond the initially available surface by up to 20% during the two hours reaction investigated. FTIR and solid-state NMR spectra both suggest the reaction of surface primary hydroxy groups with sulfamic acid. While the apparent lateral crystallite size of cotton is unaffected by sulfation treatment, X-ray diffraction suggested that homogenization resulted in cellulose nanofibers (CNFs) with a crystallite width below 3 nm, much smaller than the initial cellulose microfibrils (6–7 nm). This apparent crystallite splitting during homogenization suggests that cotton microfibrils have an intertwined polycrystalline structure, rather than being monocrystalline along the whole length. [ABSTRACT FROM AUTHOR]

In the current study, two series of catalysts were synthesized and characterized by various physicochemical techniques. In the first series of catalysts, a chemical precipitation method was used for loading 1–20 wt. % ZrO2 on the surface of sugarcane bagasse fly ash (SCBFA) with the goal of finding out the optimal ZrO2 loading. In the second series, the 20% ZrO2/SCBFA composition was modified by (1–10 wt. %) SO42− by wet impregnation method. The acidity of these catalysts was determined through the dehydration of isopropyl alcohol and the chemisorption of pyridine and 2,6-dimethyl pyridine. The catalytic efficiency for the dehydration of methanol to dimethyl ether (DME) in a fixed-bed reactor at atmospheric pressure was investigated. A ~ 95% yield toward DME is maximized over the 10% SO42−/20% ZrO2/SCBFA catalyst at a reaction temperature of 400°C. Additionally, it maintained nearly the same efficiency over a 90-h period and demonstrated outstanding long-term stability. The specific surface area and the acidity are the most important factors responsible for enhancing the catalytic performance in this reaction. Our study reflects that SCBFA-supported zirconia and that modified with SO42− are low-cost, effective, eco-friendly, and recyclable catalysts that are highly suited to apply for production of DME from methanol. [ABSTRACT FROM AUTHOR]

In COPD, chronic inflammation and exposure to irritants, such as cigarette smoke, lead to the thickening of bronchial walls. This results from increased deposition of collagen and other extracellular matrix components, contributing to the narrowing of airways. Nevertheless, it is widely recognized that COPD is an inflammatory disorder marked by partially reversible airflow limitation wherein genetic factors interact with the environment. In recent years, numerous investigations have substantiated the correlation between gene polymorphisms and COPD. SUMF1 has been implicated in diverse cellular processes, including lysosomal function and extracellular matrix maintenance, both of which play pivotal roles in respiratory health. The genetic variations in SUMF1 could lead to an imbalanced sulfation in the extracellular matrix of lung tissue, potentially playing a role in the onset of COPD. Recent studies have uncovered a potential link between dysregulation of SUMF1 and COPD progression, shedding light on its involvement in the abnormal sulfatase activity observed in COPD patients. Through a comprehensive review of current literature and experimental findings, this article aims to contribute to the growing body of knowledge surrounding the genetic intricacies concerning sulfation of airway remodeling and possible pharmacological applications in COPD and asthma management. [ABSTRACT FROM AUTHOR]

This study involved the creation of highly porous PLA scaffolds through the porogen/leaching method, utilizing polyethylene glycol as a porogen with a 75% mass ratio. The outcome achieved a highly interconnected porous structure with a thickness of 25 μm. To activate the scaffold's surface and improve its hydrophilicity, radiofrequency (RF) air plasma treatment was employed. Subsequently, furcellaran subjected to sulfation or carboxymethylation was deposited onto the RF plasma treated surfaces with the intention of improving bioactivity. Surface roughness and water wettability experienced enhancement following the surface modification. The incorporation of sulfate/carboxymethyl group (DS = 0.8; 0.3, respectively) is confirmed by elemental analysis and FT-IR. Successful functionalization of PLA scaffolds was validated by SEM and XPS analysis, showing changes in topography and increases in characteristic elements (N, S, Na) for sulfated (SF) and carboxymethylated (CMF). Cytocompatibility was evaluated by using mouse embryonic fibroblast cells (NIH/3T3). [ABSTRACT FROM AUTHOR]

Sulfonation, primarily facilitated by sulfotransferases, plays a crucial role in the detoxification pathways of endogenous substances and xenobiotics, promoting metabolism and elimination. Traditionally, this bioconversion has been attributed to a family of human cytosolic sulfotransferases (hSULTs) known for their high sequence similarity and dependence on 3′-phosphoadenosine 5′-phosphosulfate (PAPS) as a sulfo donor. However, recent studies have revealed the presence of PAPS-dependent sulfotransferases within gut commensals, indicating that the gut microbiome may harbor a diverse array of sulfotransferase enzymes and contribute to detoxification processes via sulfation. In this study, we investigated the prevalence of sulfotransferases in members of the human gut microbiome. Interestingly, we stumbled upon PAPS-independent sulfotransferases, known as aryl-sulfate sulfotransferases (ASSTs). Our bioinformatics analyses revealed that members of the gut microbial genus Sutterella harbor multiple asst genes, possibly encoding multiple ASST enzymes within its members. Fluctuations in the microbes of the genus Sutterella have been associated with various health conditions. For this reason, we characterized 17 different ASSTs from Sutterella wadsworthensis 3_1_45B. Our findings reveal that SwASSTs share similarities with E. coli ASST but also exhibit significant structural variations and sequence diversity. These differences might drive potential functional diversification and likely reflect an evolutionary divergence from their PAPS-dependent counterparts. [ABSTRACT FROM AUTHOR]

Posttranslational modifications (PTMs) are covalent modifications of proteins that modulate the structure and functions of proteins and regulate biological processes. The development of various mass spectrometry‐based proteomics workflows has facilitated the identification of hundreds of PTMs and aided the understanding of biological significance in a high throughput manner. Improvements in sample preparation and PTM enrichment techniques, instrumentation for liquid chromatography‐tandem mass spectrometry (LC‐MS/MS), and advanced data analysis tools enhance the specificity and sensitivity of PTM identification. Highly prevalent PTMs like phosphorylation, glycosylation, acetylation, ubiquitinylation, and methylation are extensively studied. However, the functions and impact of less abundant PTMs are not as well understood and underscore the need for analytical methods that aim to characterize these PTMs. This review focuses on the advancement and analytical challenges associated with the characterization of three less common but biologically relevant PTMs, specifically, adenosine diphosphate‐ribosylation, tyrosine sulfation, and tyrosine nitration. The advantages and disadvantages of various enrichment, separation, and MS/MS techniques utilized to identify and localize these PTMs are described. [ABSTRACT FROM AUTHOR]

Histone H3 tyrosine-99 sulfation (H3Y99sulf) is a recently identified histone mark that can cross-talk with H4R3me2a to regulate gene transcription, but its role in cancer biology is less studied. Here, we report that H3Y99sulf is a cancer-associated histone mark that can mediate hepatocellular carcinoma (HCC) cells responding to hypoxia. Hypoxia-stimulated SNAIL pathway elevates the expression of PAPSS2, which serves as a source of adenosine 30-phosphate 50-phos-phosulfate for histone sulfation and results in upregulation of H3Y99sulf. The transcription factor TDRD3 is the downstream effector of H3Y99sulf-H4R3me2a axis in HCC. It reads and co-localizes with the H3Y99sulf-H4R3me2a dual mark in the promoter regions of HIF1A and PDK1 to regulate gene transcription. Depletion of SULT1B1 can effectively reduce the occurrence of H3Y99sulf-H4R3me2a-TDRD3 axis in gene promoter regions and lead to downregulation of targeted gene transcription. Hypoxia-inducible factor 1-alpha and PDK1 are master regulators for hypoxic responses and cancer metabolism. Disruption of the H3Y99sulf-H4R3me2a-TDRD3 axis can inhibit the expression and functions of hypoxia-inducible factor 1-alpha and PDK1, resulting in suppressed proliferation, tumor growth, and survival of HCC cells suffering hypoxia stress. The present study extends the regulatory and functional mechanisms of H3Y99sulf and improves our understanding of its role in cancer biology. [ABSTRACT FROM AUTHOR]

Ticks pose a substantial public health risk as they transmit various pathogens. This concern is related to the adept blood-sucking strategy of ticks, underscored by the action of the anticoagulant, madanin, which is known to exhibit an approximately 1000-fold increase in anticoagulant activity following sulfation of its two tyrosine residues, Tyr51 and Tyr54. Despite this knowledge, the molecular mechanism underlying sulfation by tick tyrosylprotein sulfotransferase (TPST) remains unclear. In this study, we successfully prepared tick TPST as a soluble recombinant enzyme. We clarified the method by which this enzyme proficiently sulfates tyrosine residues in madanin. Biochemical analysis using a substrate peptide based on madanin and tick TPST, along with the analysis of the crystal structure of the complex and docking simulations, revealed a sequential sulfation process. Initial sulfation at the Tyr51 site augments binding, thereby facilitating efficient sulfation at Tyr54. Beyond direct biochemical implications, these findings considerably improve our understanding of tick bloodsucking strategies. Furthermore, combined with the utility of modified tick TPST, our findings may lead to the development of novel anticoagulants, promising avenues for thrombotic disease intervention and advancements in the field of public health. [ABSTRACT FROM AUTHOR]

3'-Phosphoadenosine 5'-phosphosulfate synthase 2 (PAPSS2) deficiency is a rare disorder due to biallelic pathogenic variants in the PAPSS2 gene. This disorder was first described in 1998 by Ahmad et al. and Faiyaz ul Haque et al. To date, 79 patients with PAPSS2 deficiency have been reported. The main reported features of these patients are related to bone abnormalities and clinical/biochemical androgen excess. Disproportionate short stature and symptoms associated with spondylar skeletal dysplasia are the most common clinical features that require clinical attention. Androgen excess has been described much less commonly. This review summarizes the currently published clinical, molecular, and biochemical features of patients with PAPSS2 deficiency. [ABSTRACT FROM AUTHOR]

Sulfation is a crucial and prevalent conjugation reaction involved in cellular processes and mammalian physiology. 3′-Phosphoadenosine 5′-phosphosulfate (PAPS) synthase 2 (PAPSS2) is the primary enzyme to generate the universal sulfonate donor PAPS. The involvement of PAPSS2-mediated sulfation in adenomatous polyposis coli (APC) mutation-promoted colonic carcinogenesis has not been reported. Here, we showed that the expression of PAPSS2 was decreased in human colon tumors along with cancer stages, and the lower expression of PAPSS2 was correlated with poor prognosis in advanced colon cancer. Gut epithelial-specific heterozygous Apc deficient and Papss2 -knockout (Apc Δgut-Het Papss2 Δgut) mice were created, and the phenotypes were compared to the spontaneous intestinal tumorigenesis of Apc Δgut-Het mice. Apc Δgut-Het Papss2 Δgut mice were more sensitive to gut tumorigenesis, which was mechanistically accounted for by the activation of Wnt/ β -catenin signaling pathway due to the suppression of chondroitin sulfation and inhibition of the farnesoid X receptor (FXR)-transducin-like enhancer of split 3 (TLE3) gene regulatory axis. Chondroitin sulfate supplementation in Apc Δgut-Het Papss2 Δgut mice alleviated intestinal tumorigenesis. In summary, we have uncovered the protective role of PAPSS2-mediated chondroitin sulfation and bile acids–FXR–TLE3 activation in the prevention of gut carcinogenesis via the antagonization of Wnt/ β -catenin signaling. Chondroitin sulfate may be explored as a therapeutic agent for Papss2 deficiency-associated colonic carcinogenesis. Intestinal PAPSS2 or sulfation represents a potential therapeutic target for colon cancer and chondroitin sulfate may be explored for its use in the prevention and treatment of PAPSS2 deficiency-associated colon cancer. [Display omitted] [ABSTRACT FROM AUTHOR]

Poly‐proline II helices are secondary structure motifs frequently found in ligand‐binding sites. They exhibit increased flexibility and solvent exposure compared to the strongly hydrogen‐bonded α‐helices or β‐strands and can therefore easily be misinterpreted as completely unstructured regions with an extremely high rotational freedom. Here, we show that the adhesin YadA of Yersinia enterocolitica serotype O:9 contains a poly‐proline II helix interaction motif in the N‐terminal region. The motif is involved in the interaction of YadAO:9 with heparin, a host glycosaminoglycan. We show that the basic residues within the N‐terminal motif of YadA are required for electrostatic interactions with the sulfate groups of heparin. Biophysical methods including CD spectroscopy, solution‐state NMR and SAXS all independently support the presence of a poly‐proline helix allowing YadAO:9 binding to the rigid heparin. Lastly, we show that host cells deficient in sulfation of heparin and heparan sulfate are not targeted by YadAO:9‐mediated adhesion. We speculate that the YadAO:9–heparin interaction plays an important and highly strain‐specific role in the pathogenicity of Yersinia enterocolitica serotype O:9. [ABSTRACT FROM AUTHOR]

Polychlorinated biphenyls (PCBs) are persistent organic toxicants derived from legacy pollution sources and their formation as inadvertent byproducts of some current manufacturing processes. Metabolism of PCBs is often a critical component in their toxicity, and relevant metabolic pathways usually include their initial oxidation to form hydroxylated polychlorinated biphenyls (OH-PCBs). Subsequent sulfation of OH-PCBs was originally thought to be primarily a means of detoxication; however, there is strong evidence that it may also contribute to toxicities associated with PCBs and OH-PCBs. These contributions include either the direct interaction of PCB sulfates with receptors or their serving as a localized precursor for OH-PCBs. The formation of PCB sulfates is catalyzed by cytosolic sulfotransferases, and, when transported into the serum, these metabolites may be retained, taken up by other tissues, and subjected to hydrolysis catalyzed by intracellular sulfatase(s) to regenerate OH-PCBs. Dynamic cycling between PCB sulfates and OH-PCBs may lead to further metabolic activation of the resulting OH-PCBs. Ultimate toxic endpoints of such processes may include endocrine disruption, neurotoxicities, and many others that are associated with exposures to PCBs and OH-PCBs. This review highlights the current understanding of the complex roles that PCB sulfates can have in the toxicities of PCBs and OH-PCBs and research on the varied mechanisms that control these roles. [ABSTRACT FROM AUTHOR]

Structure and function of therapeutic antibodies can be modulated by a variety of post-translational modifications (PTM). Tyrosine (Tyr) sulfation is a type of negatively charged PTM that occurs during protein trafficking through the Golgi. In this study, we discovered that an anti-interleukin (IL)-4 human IgG1, produced by transiently transfected HEK293 cells, contained a fraction of unusual negatively charged species. Interestingly, the isolated acidic species exhibited a two-fold higher affinity to IL-4 and a nearly four-fold higher potency compared to the main species. Mass spectrometry (MS) showed the isolated acidic species possessed an +80-Dalton from the expected mass, suggesting an occurrence of Tyr sulfation. Consistent with this hypothesis, we show the ability to control the acidic species during transient expression with the addition of Tyr sulfation inhibitor sodium chlorate or, conversely, enriched the acidic species from 30% to 92% of the total antibody protein when the IL-4 IgG was co-transfected with tyrosylprotein sulfotransferase genes. Further MS and mutagenesis analysis identified a Tyr residue at the light chain complementarity-determining region-1 (CDRL-1), which was sulfated specifically. These results together have demonstrated for the first time that Tyr sulfation at CDRL-1 could modulate antibody binding affinity and potency to a human immune cytokine. [ABSTRACT FROM AUTHOR]

Seaweed polysaccharides can act as substitutes for synthetic compounds present in commercial stimulants and fertilizers used in agriculture to improve crop yields and vigor. In this study, three different polysaccharides (alginate, agar, and carrageenan) were extracted from one brown seaweed, Saccorhiza polyschides, and two red seaweeds, Gracilaria gracilis and Chondrus crispus, respectively, and applied to potted turnip greens (Brassica napus L.), with the intention to analyze their impact on plant growth, development, and metabolism. Turnip greens treated with polysaccharides, especially carrageenan of C. crispus, showed the best results in improving the crop productivity in terms of plant length and weight, number of leaves, nutrient and pigment content, and soil fertility compared with turnip greens from the negative control or those treated with a commercial leaf fertilizer. λ-carrageenan extracted from the tetrasporophyte generation of C. crispus had the highest bioactivity and positive effect on turnip greens among all treatments. λ-carrageenan has been shown to improve plant growth; increase the plant's biomass (plant leaves: CC(T) (40.80 ± 5.11 g) compared to the positive control (15.91 ± 15.15 g)) and root system; enhance photosynthetic activity; increase the uptake of soil nutrients; and protect plants against abiotic and biotic stresses, stimulating the production of secondary metabolites and managing its defense pathways. Seaweed-extracted polysaccharides have the potential to be used in sustainable agriculture. [ABSTRACT FROM AUTHOR]

Betulin is a biologically active triterpenoid substance, which can be isolated from birch bark. We report on a new approach to the synthesis of betulin sulfamate with sulfamic acid and ammonium sulfamate in the presence of solid catalysts, including Amberlyst 15® and Sibunit (granules) oxidized at 500 °C, Sibunit (powder) oxidized at 400 °C, Sibunit-sulfated, TiO2, and ɣ-Al2O3. It is shown that the synthesis with both sulfamic acid and ammonium sulfamate in the presence of an Amberlyst 15® catalyst yields sulfur derivatives of betulin. This catalyst has been proven to remain active at the repeated (up to four cycles) use. A reaction scheme for the catalytic production of sulfur derivatives of betulin is proposed. The obtained sulfur derivatives of betulin have been examined by Fourier transform infrared and ultraviolet visible spectroscopy, scanning electron and optical microscopy, X-ray diffractometry, thermogravimetric analysis, differential scanning calorimetry, and elemental analysis. It has been found by Fourier transform infrared spectroscopy that the use of sulfamic acid with an Amberlyst 15® catalyst ensures the formation of betulin sulfates, while when using ammonium sulfamate with the same catalyst, the sulfate and other betulin derivatives are obtained along with sulfates. It has been established from the X-ray diffractometry data that sulfation of betulin causes its stronger amorphization. [ABSTRACT FROM AUTHOR]

The HUMMIC skin–liver Chip2 microphysiological system using EpiDerm™ and HepaRG and stellate liver spheroids was used to evaluate the route‐specific metabolism and toxicodynamic effects of genistein. Human‐relevant exposure levels were compared: 60 nM representing the plasma concentration expected after topical application of a cosmetic product and 1 μM representing measured plasma concentrations after ingesting soya products. Genistein was applied as single and repeated topical and/or systemic doses. The kinetics of genistein and its metabolites were measured over 5 days. Toxicodynamic effects were measured using transcriptional analyses of skin and liver organoids harvested on Days 2 and 5. Route‐specific differences in genistein's bioavailability were observed, with first‐pass metabolism (sulfation) occurring in the skin after topical application. Only repeated application of 1 μM, resembling daily oral intake of soya products, induced statistically significant changes in gene expression in liver organoids only. This was concomitant with a much higher systemic concentration of genistein which was not reached in any other dosing scenario. This suggests that single or low doses of genistein are rapidly metabolised which limits its toxicodynamic effects on the liver and skin. Therefore, by facilitating longer and/or repeated applications, the Chip2 can support safety assessments by linking relevant gene modulation with systemically available parent or metabolite(s). The rate of metabolism was in accordance with the short half‐life observed in in vivo in humans, thus supporting the relevance of the findings. In conclusion, the skin–liver Chip2 provides route‐specific information on metabolic fate and toxicodynamics that may be relevant to safety assessment. The HUMMIC skin‐liver Chip2 microphysiological system was used to evaluate the route‐specific metabolism and toxicodynamic effects of dietary (1 μM) and cosmetic (60 nM) relevant doses of genistein. First‐pass metabolism occurred in the skin after topical application. Only repeated application of 1 μM significantly changed gene expression in liver organoids. The short half‐life observed in in vivo in humans was replicated in the Chip2. This model can support safety assessments by linking gene effects with systemically available parent or metabolite(s). [ABSTRACT FROM AUTHOR]

Xylan sulfation using a Deep Eutectic Solvent (DES), formed by sulfamic acid and urea (1:2 molar ratio), was investigated with different reagent dosages (xylan/sulfamic acid molar ratio 1:10 and 1:5) and time (30 and 60 min). The effect of xylan/reagent ratio on the degree of substitution (DS) was higher than time, varying from 0.4 to 1.1. NMR spectra confirmed that the sulfate group was introduced into the C-2 and C-3 of the xylose moieties. Polyelectrolyte complex suspensions were prepared using the different sulfated xylan (SXyl) and chitosan (Ch) (mass ratio 55 SXyl/45 Ch) and deeply characterized. It was found that a precipitate was obtained for moderate conditions of sulfation; however for the others, stable suspensions were formed. Hydrogels with acceptable dry and wet mechanical properties (up to 45 MPa and 6 MPa of resistance, and 10% and 90% of elongation, respectively), and thermal properties were produced. Differences in crystallinity as well as in water uptake at 75% RH, depending on the SXyl used, were found. Promising results for potential use in drug delivery were the swelling capacity, which reached a maximum of 384% and was directly related to the degree of substitution of xylan, and the high water-resistant. [ABSTRACT FROM AUTHOR]

Sulfated polysaccharides of brown algae, fucoidans, are known for their anticoagulant properties, similar to animal heparin. Their complex and irregular structure is the main bottleneck in standardization and in defining the relationship between their structure and bioactivity. Fucoidan-active enzymes can be effective tools to overcome these problems. In the present work, we identified the gene fwf5 encoding the fucoidan-active endo-fucanase of the GH168 family in the marine bacterium Wenyingzhuangia fucanilytica CZ1127T. The biochemical characteristics of the recombinant fucanase FWf5 were investigated. Fucanase FWf5 was shown to catalyze the endo-type cleavage of the 1→4-O-glycosidic linkages between 2-O-sulfated α-L-fucose residues in fucoidans composed of the alternating 1→3- and 1→4-linked residues of sulfated α-L-fucose. This is the first report on the endo-1→4-α-L-fucanases (EC 3.2.1.212) of the GH168 family. The endo-fucanase FWf5 was used to selectively produce high- and low-molecular-weight fucoidan derivatives containing either regular alternating 2-O- and 2,4-di-O-sulfation or regular 2-O-sulfation. The polymeric 2,4-di-O-sulfated fucoidan derivative was shown to have significantly greater in vitro anticoagulant properties than 2-O-sulfated derivatives. The results have demonstrated a new type specificity among fucanases of the GH168 family and the prospects of using such enzymes to obtain standard fucoidan preparations with regular sulfation and high anticoagulant properties. [ABSTRACT FROM AUTHOR]

Sulfated polysaccharides are important promising biologically active substances with anticoagulant properties. Biological activity is affected by the method of preparation, as well as the type of the polysaccharide and its molecular structure. In this work, we have considered various methods for the synthesis of promising anticoagulants – polysaccharide sulfates using the example of obtaining agarose sulfate. We compared various sulfating agents: chlorosulfonic acid, sulfamic acid, with various activators, and a deep eutectic solvent mixture of sulfamic acid with urea (in the melt). It has been shown that when urea is used as an activator of the process of sulfation of agarose with sulfamic acid in 1,4-dioxane, agarose sulfate with a high sulfur content (up to 14.5 wt%) is formed, which is close to the use of chlorosulfonic acid as a sulfating agent (with the production of agarose sulfate with 15.0 wt% sulfur). The use of solid catalysts in the process of sulfation of agarose with sulfamic acid leads to the production of agarose sulfate with a sulfur content of up to 14.1 wt% (for a catalyst based on the oxidized carbonaceous material Sibunit-4®). Sulfation of agarose in a deep eutectic solvent – a mixture of sulfamic acid with urea – leads to the production of agarose sulfate with a sulfur content of up to 13.7 wt%. The resulting agarose sulfates were characterized by FTIR spectroscopy, X-ray diffraction, elemental analysis, atomic force microscopy and DFT. [ABSTRACT FROM AUTHOR]

Arabinogalactan is a biologically active water-soluble polysaccharide contained in great amounts in larch wood. A sulfate group introduced into the arabinogalactan molecule increases its biological activity and imparts new anticoagulant and hypolipedemic properties. A new method for the catalytic sulfation of arabinogalactan with ammonium sulfamate is proposed. The catalytic activity in the reaction of arabinogalactan sulfation with ammonium sulfamate has been investigated for both the base activators (urea and thiourea) and oxidants (KMnO4 and K2Cr2O7). It has been shown that, in this process, the most effective activator is KMnO4, which ensures the highest (11.3 wt %) sulfur content in sulfated arabinogalactan. The effect of temperature and time of the arabinogalactan sulfation with ammonium sulfamate and the nature of solvents used on the sulfur content in sulfated arabinogalactan has been examined. It has been found that the highest (11.3%) sulfur content in the product is obtained by sulfation of arabinogalactan in 1,4-dioxane at a temperature of 90 °C for 4 h with the KMnO4 activator. The introduction of a sulfate group into the arabinogalactan molecule has been confirmed by the FTIR and NMR spectroscopy data. The FTIR spectrum of sulfated arabinogalactan, in contrast to that of the initial arabinogalactan, includes an absorption band at 1249 cm−1. According to the 13C NMR spectroscopy data, the sulfate groups are located at carbon atoms C2 and C4 of the main galactan chain and at carbon atom C6 of the end galactose units of the main and side arabinogalactan chains. It has been established by gel permeation chromatography that, during the sulfation, the molecular mass of arabinogalactan molecules increases proportionally to the introduced sulfate groups. The absence of low molecular weight fractions is indicative of the absence of depolymerization under the conditions of sulfation and evolution of sulfated arabinogalactan. [ABSTRACT FROM AUTHOR]

Gaseous SO2 acidification Ce-based catalysts were prepared and used for the selective reduction of NO with NH3. S–Ce was obtained by direct anaerobic sulfation of CeO2, while H–S–Ce was obtained by reduction of CeO2 and then anaerobic sulfation. Both S–Ce and H–S–Ce exhibited excellent SCR activity, and the S–Ce catalyst displayed the best catalytic performance. The activity of CeO2 was below 30% in the whole temperature range, while the activity of S–Ce reached 90% at 250 °C and remained 100% at 300–450 °C. Anaerobic sulfation could enhance the redox and surface acidity of the S–Ce catalyst. The acid sites favored NH3 adsorption, while the H–S–Ce catalyst exhibited considerable surface acidity, but the redox performance was weakened by stable sulfate. The reaction mechanism showed that a huge number of NH3 species adsorbed on S–Ce catalysts were consumed by NO gas. The present nitrate species and NO2 were removed. The SCR reaction followed E–R and L–H mechanisms for S–Ce. A large number of NH3 species on H–S–Ce were cleared by NO, and NO could hardly adsorb on its surface. The SCR reaction followed the E–R mechanism. [ABSTRACT FROM AUTHOR]

Gaseous SO2 acidification Ce-based catalysts were prepared and used for the selective reduction of NO with NH3. S–Ce was obtained by direct anaerobic sulfation of CeO2, while H–S–Ce was obtained by reduction of CeO2 and then anaerobic sulfation. Both S–Ce and H–S–Ce exhibited excellent SCR activity, and the S–Ce catalyst displayed the best catalytic performance. The activity of CeO2 was below 30% in the whole temperature range, while the activity of S–Ce reached 90% at 250 °C and remained 100% at 300–450 °C. Anaerobic sulfation could enhance the redox and surface acidity of the S–Ce catalyst. The acid sites favored NH3 adsorption, while the H–S–Ce catalyst exhibited considerable surface acidity, but the redox performance was weakened by stable sulfate. The reaction mechanism showed that a huge number of NH3 species adsorbed on S–Ce catalysts were consumed by NO gas. The present nitrate species and NO2 were removed. The SCR reaction followed E–R and L–H mechanisms for S–Ce. A large number of NH3 species on H–S–Ce were cleared by NO, and NO could hardly adsorb on its surface. The SCR reaction followed the E–R mechanism. [ABSTRACT FROM AUTHOR]

The new low‐cost clean pre‐desulfation technology is very important in pyrometallurgy and hydrometallurgy. However, traditional reactors have low space‐time yield and desulfation rate, resulting in high energy consumption and SO2 emissions in the industrial desulfation processes. Herein, dual rotating liquid film reactors (RLFRs) and lime are proposed to construct a recyclable, ultra‐fast, and value‐added desulfation method. Parameter optimization and kinetic calculations prove that the above reactions are controlled by internal diffusion, revealing that RLFR promotes the mass transfer and reaction rate. The new process greatly shortens the desulfation time of lead paste from 40 min to 10 s with a high desulfation rate of 99.7%, and the sulfation time of lime from 30 min to 30 s with a sulfation rate of 98.6% with a net profit of 55.99 ¥/ton by cost accounting. Moreover, ten batches of continuous scale‐up experiments demonstrate the stability of processes, the desulfation and sulfation rates are kept at 99.7% and 98.2%, which greatly reduces the emissions of waste desulfate liquor. This work provides a new universal strategy for a sustainable, low‐cost, and clean desulfation method of waste resources to achieve technical and economic feasibility. [ABSTRACT FROM AUTHOR]

Spent lithium-ion batteries (LIBs) are an essential secondary resource containing valuable metal elements. The recovery of valuable metals from spent LIBs poses immense importance in terms of environmental protection and mitigating resource shortages. Sulfation roasting has been demonstrated to have high efficiency in recovering valuable elements from spent LIBs. Nevertheless, conventional sulfation roasting techniques have certain drawbacks, such as lack of sustainability and an adverse environmental impact, due to the utilization of costly sulfation reagents and the emission of SO2. Herein, a green strategy involving waste copperas-assisted sulfation and roasting–water leaching process with SO2-free emissions is proposed to selectively recover lithium and prepare low-cost LIB-derived CoFe2O4 catalysts from spent lithium cobalt oxide (LCO) batteries. Under optimal conditions, approximately 92.87% of lithium in the LCO battery cathode could be successfully recovered as Li2CO3 with a purity of 99.69%. Additionally, the prepared LIB-derived CoFe2O4 catalyst showed an excellent CO catalytic activity at 300 °C, with about 98% of CO being effectively oxidized. The catalysis process followed a Mars–van Krevelen-type mechanism, where CO was oxidized by the interaction with the adsorbed oxygen species and lattice oxygen. This strategy is the first to combine the selective recovery of lithium with CO purification, achieving the efficient and functional utilization of spent LIBs and providing a new strategy for treating spent LIBs. [ABSTRACT FROM AUTHOR]

In this work, the roasting of an enargite mix was carried out in oxidative conditions. The temperature range of the study was 773–973 K. The mixture had a 4:6:6 molar ratio of enargite, magnetite and coal, respectively. The roasting was made in an open atmosphere. The time was 1 h for each isothermal test. The effect of temperature and weight loss were studied. The results indicate that the temperature affects the products. At 773–873 K, the copper phases were sulfates. When the temperature was increased to 973 K, all the present phases were oxidized, and no arsenic phase was encountered in the XRDs. Therefore, this process is an excellent alternative for roasting copper concentrates with enargite, removing arsenic in the gas phase and generating a calcine that could then go to lixiviation to finally recover the copper through electrowinning. [ABSTRACT FROM AUTHOR]

Lead-acid batteries are noted for simple maintenance, long lifespan, stable quality, and high reliability, widely used in the field of energy storage. However, during the use of lead-acid batteries, the negative electrode is prone to irreversible sulfation, failing to meet the requirements of new applications such as maintenance-free hybrid vehicles and solar energy storage. In this study, in order to overcome the sulfation problem and improve the cycle life of lead-acid batteries, active carbon (AC) was selected as a foaming agent and foam fixing agent, and carbon foams (CF) with layered porous structure was prepared by mixing with molten sucrose. Sucrose as raw material is green and cheap, and the material preparation process is simple. The prepared CF material was then added as an additive to the negative electrode plate, and the electrochemical performance of the electrode plate and the battery was studied. The results proved that the addition of CF could effectively inhibit the sulfate formation of the negative electrode plate, with the 1.0 % CF negative electrode plate showing the best electrochemical performance. Specifically, according to the result of battery cycle testing, the simulated battery with CF had a cycle life of 3642 times, which was 2.87 times that of the blank group and 2.39 times of the AC group. Meanwhile, rate testing showed that the simulated battery with CF could maintain a high capacity even under high-rate discharge conditions.

In this study, polysaccharides were extracted at a rate of 87.5% ± 1.5% from native dandelion roots, and the dandelion root polysaccharides (DRPs) were then chemically modified to obtain sulfated polysaccharides (SDRPs) with a degree of substitution of 1.49 ± 0.07. The effects of modification conditions, physicochemical characterizations, structural characteristics, antioxidant properties, hypoglycemic activity, and proliferative effects on probiotics of DRP derivatives were further investigated. Results showed that the optimum conditions for sulfation of DRPs included esterification reagents (concentrated sulfuric acid: n-butanol) ratio of 3:1, a reaction temperature of 0 °C, a reaction time of 1.5 h, and the involvement of 0.154 g of ammonium sulfate. The DRPs and SDRPs were composed of six monosaccharides, including mannose, glucosamine, rhamnose, glucose, galactose, and arabinose. Based on infrared spectra, the peaks of the characteristic absorption bands of S=O and C-O-S appeared at 1263 cm−1 and 836 cm−1. Compared with DRPs, SDRPs had a significantly lower relative molecular mass and a three-stranded helical structure. NMR analysis showed that sulfated modification mainly occurred on the hydroxyl group at C6. SDRPs underwent a chemical shift to higher field strength, with their characteristic signal peaking in the region of 1.00–1.62 ppm. Scanning electron microscopy (SEM) analysis indicated that the surface morphology of SDRPs was significantly changed. The structure of SDRPs was finer and more fragmented than DRPs. Compared with DRPs, SDRPs showed better free radical scavenging ability, higher Fe2+chelating ability, and stronger inhibition of α-glucosidase and α-amylase. In addition, SDRPs had an excellent promotional effect on the growth of Lactobacillus plantarum 10665 and Lactobacillus acidophilus. Therefore, this study could provide a theoretical basis for the development and utilization of DRPs.

Mathematical modeling of columnar leaching is a useful tool for predicting and evaluating the kinetics of copper extraction. One commonly used model for this process is the shrinking core model (SCM). In this study, the aim was to develop a model for column leaching of oxidized copper ore based on the SCM, which incorporates the ore sulfation stage before leaching. In sulfation and leaching laboratory-scale tests, we studied the effect of acid dosage (at 22.8, 34.2, and 45.6 kg/t), humidity (at 90%, 100%, and 110% of the saturation humidity of the mineral), ore granulometry (−3/4″ and −3/8″), and rest time (at 24, 48, 72, and 96 h) on sulfation. We found that the highest sulfation reached 49.7% for both granulometries in studies. In the column tests, the effects of acid dosage (at 34.2, 45.6 kg/t), ore granulometry (−3/4″, −3/8″), and rest time (at 24, 48 h) were studied. When the SCM was applied to these tests, we obtained fit qualities within 63.4% and 74.9%. By incorporating the sulfation factor into the SCM predictions, we observed an average increase in adjustment between 24% and 28%. This method is effective for minerals and operating conditions different from the ones studied.

Objective: To establish a preparation method of Atractylodes macrocephala Koidz polysaccharide (AMP) sulfate with anti-hyperplasia of mammary. Methods: AMP were sulfated by sulfated method, and the optimal conditions for the sulfated modification were determined by response surface methodology. The structures of AMP and SAMP were initially analyzed by infrared spectroscopy (IR) and High-Performance Gel Chromatography (HPGPC). The anti-oxidative activity in vitro of polysaccharide was investigated by testing the DPPH, ABTS+, OH free radical scavenging ability of AMP and SAMP. Rat model of mammary gland hyperplasia was established by intramuscular injection of estradiol benzoate and progesterone. The rats weight and breast diameter were recorded and the pathological organization form of mammary gland of rats were observed. Results: The optimum preparation conditions were as follows: Ratio of conditions of volume ratio of sulfuric acid and n-butanol 2:1, reaction temperature −4 ℃, reaction time 21 min. The degree of substitution of SAMP was 0.59±0.00391. The HPGPC results showed the relative molecular weights for AMP and SAMP were 2719 and 33524 Da, respectively. The IR spectra showed that SAMP had characteristic absorption peaks of S=O and C-O-S appeared near 833 and 1226 cm−1, indicating that the sulfated was successful. When the sample concentration was 0.5 mg/mL, the DPPH, ABTS+, OH free radical scavenging activities of SAMP were 54.91% , 38.21%, and 42.23%, respectively. Compared with the model group, the diameter of the nipples of the rats in the SAMP group decreased (P

This study aimed to determine the effect of sulfated xylans on the growth of probiotics. Xylan (Xyl) was chemically modified using the sulfamic acid-N,N-dimethylformamide method to produce sulfated xylan (SXY). The SXY was characterized by Fourier infrared spectroscopy (FT-IR), scanning electron microscope (SEM) and Congo red experiment. The Xyl and SXY were tested for their in vitro prebiotic effects using four strains of intestinal microflora, including Lactobacillus delbrueckii subsp. bulgaricus (GIM1.155), L. plantarum (GIM1.191), L. brevis (GIM1.773), and Streptococcus thermophilus (GIM1.540). From the recorded infrared spectra, vibrational bands for SXY were observed at 894, 1052 and 1243 cm−1, they could be assigned to the C—O—S vibration of a C—O—SO3, C—O stretched and S＝O stretching vibrations. The results of scanning electron microscopy showed that the surface structure of SXY increased smoothness. Congo red experiment revealed that SXY had a triple helix structure. The substitution degree of SXY measured using a BaCl2-gelatin turbidimeter was 0.341. In vitro experiment showed that the optimum concentration of SXY for the in vitro probiotic growth was 2.0%, rapid growth and increased proliferation were observed after 10 h of culture. The results obtained suggest that SXY could promote probiotic growth. It is an alternate source of prebiotics for maintaining gut health.

Zizania latifolia is a highly nutritious vegetable being praised as “Ginseng in Water”. Polysaccharides are the main bioactive ingredients in Z. latifolia, but there have been no reports on the yield- and activity-guided ultrasonic-assisted extraction (UAE), sulfation and anti-non-small cell lung cancer (NSCLC) activity. In this study, Z. latifolia polysaccharides (ZLP) were extracted using UAE under an optimized power, followed by sulfation to give three derivatives (SZLP-1 ∼ 3). After characterization, the antioxidant and anti-NSCLC activities were evaluated. The optimal ultrasonic power for ZLP extraction was screened out to be 300 W, under which the yield was 16.9 ± 2.10 %, and the scavenging rate against 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical was 63.3 ± 5.71 %, significantly higher than those of other powers and hot-water extraction. A series of characterizations fully confirmed the sulfated modification of ZLP. Sulfation improved the antioxidation of ZLP and was positively proportional to the degree of substitution (DS), of which SZLP-2 with a DS of 15.1 ± 2.50 elicited strong hydroxyl and DPPH radicals-scavenging capacities. Meanwhile, SZLP-2 also exerted promising anti-NSCLC potency via inhibiting A549 cell proliferation, with a median inhibition concentration (IC50) of 0.57 ± 0.01 mg/mL at 72 h, markedly smaller than that of unmodified ZLP (0.78 ± 0.04 mg/mL). In summary, the yield- and activity-guided UAE led to the ZLP with high yield and strong antioxidation. Further sulfation enhanced the bioactivities and produced the promising SZLP-2, which showed great potential in the development of novel antioxidant and anti-NSCLC drug.

A series of Ce–Fe bimetallic oxide catalysts were prepared by a hydrothermal method for CO catalytic oxidation at a high concentration of SO2 in this paper. Ce0.7Fe0.3 showed the highest catalytic performance in CO oxidation, reaching higher than 97% CO conversion at above 300 °C in the flue gas containing 1000 ppm CO. When the concentration of SO2 in the flue gas increased to 1000 mg m−3, the CO conversion of Ce0.7Fe0.3 remained 86% for 10 hours. The doping of Fe into the CeO2 lattice resulted in the formation of a CeO2-like solid solution and the increase in the oxygen vacancy concentration in Ce0.7Fe0.3, thus facilitating the CO oxidation activity of Ce0.7Fe0.3. In the flue gas containing SO2, the doping of Fe showed positive effects of resisting the change in crystallinity and mitigating the loss of pore structure. The sulfation of CeO2 could lead to the formation of Ce2(SO4)3 on the surface, which deactivated the catalyst. The doping of Fe inhibited the reduction of Ce4+ to Ce3+ by SO2, thereby preventing the formation of Ce2(SO4)3. Furthermore, a small amount of sulfate was deposited on the surface of Ce0.7Fe0.3, exhibiting poorer thermal stability than that deposited on CeO2. The Fe-doping modification played a positive role in enhancing the CO oxidation activity and SO2-poisoning resistance of Ce0.7Fe0.3. [ABSTRACT FROM AUTHOR]

A series of Ce–Fe bimetallic oxide catalysts were prepared by a hydrothermal method for CO catalytic oxidation at a high concentration of SO2 in this paper. Ce0.7Fe0.3 showed the highest catalytic performance in CO oxidation, reaching higher than 97% CO conversion at above 300 °C in the flue gas containing 1000 ppm CO. When the concentration of SO2 in the flue gas increased to 1000 mg m−3, the CO conversion of Ce0.7Fe0.3 remained 86% for 10 hours. The doping of Fe into the CeO2 lattice resulted in the formation of a CeO2-like solid solution and the increase in the oxygen vacancy concentration in Ce0.7Fe0.3, thus facilitating the CO oxidation activity of Ce0.7Fe0.3. In the flue gas containing SO2, the doping of Fe showed positive effects of resisting the change in crystallinity and mitigating the loss of pore structure. The sulfation of CeO2 could lead to the formation of Ce2(SO4)3 on the surface, which deactivated the catalyst. The doping of Fe inhibited the reduction of Ce4+ to Ce3+ by SO2, thereby preventing the formation of Ce2(SO4)3. Furthermore, a small amount of sulfate was deposited on the surface of Ce0.7Fe0.3, exhibiting poorer thermal stability than that deposited on CeO2. The Fe-doping modification played a positive role in enhancing the CO oxidation activity and SO2-poisoning resistance of Ce0.7Fe0.3. [ABSTRACT FROM AUTHOR]

D-Glucuronic acid is a fundamental building block of many biologically important polysaccharides, either in its non-substituted form or bearing a variety of substituents, among them sulfates. We have previously performed a study of the effects of exhaustive sulfation on the conformational behavior of β-gluronopyranosides. Herein, we report an investigation comparing α- and β-derivatives of this monosaccharide within the title disaccharides using NMR and quantum chemistry approaches. It was found that for α-linked disaccharides, the introduction of sulfates did not greatly affect their conformational behavior. However, for β-derivatives, considerable conformational changes were observed. In general, they resemble those that took place for the monosaccharides, except that NOESY experiments and calculations of intra-ring spin–spin coupling constants suggest the presence of a 1S5 conformer along with 3S1 in the fully sulfated disaccharide. During the synthesis of model compounds, hydrogen bond-mediated aglycone delivery was used as an α-directing stereocontrol approach in the glucuronidation reaction. [ABSTRACT FROM AUTHOR]

Sinapic acid (SA) is ubiquitously distributed in the plant kingdom as a free organic acid and more frequently as a biosynthetic pioneer for SA derivatives, e.g., SA esters. Broad biological and pharmacological activities have been disclosed for SA. Because of the metabolism lability property, metabolites instead of the parent compound should be the primary forms after oral treatment of SA, and those metabolites should also be rapidly observed from SA following administration of SA derivative. Hence, the metabolites might provide a primary contribution to the pharmacological properties of SA; however, the metabolite profile remains unclear. Here, our efforts were devoted to addressing this issue through deploying online energy-resolved mass spectrometry (ER-MS) to accomplish isomer identification which is the key issue hindering metabolite identification, notably those conjugated metabolites. After recording breakdown graphs of concerned fragment ions with online ER-MS, the positive correlations between optimal collision energy (OCE) and bond dissociation energy (BDE) were applied to assign candidate structures to isomeric signals. Moreover, in vitro metabolism with liver cellular subfractions, UV-triggered cis-/trans-configuration transformation, and wet-chemistry hydrogenation were carried out to justify the structures. As a result, sixteen metabolites (M1−M16) were found and confirmatively identified in rat plasma and urine following SA administration, and sulfation, glucuronidation, demethylation, reduction, and dihydroxylation served as the primary metabolic channels. Noteworthily, greater distribution occurred for sulfation and glucuronidation products while inferior distributions were observed for phase I metabolites, and the half-life (T1/2) of most metabolites was greater than that of SA. This study provides a comprehensive insight into the metabolic fate of SA. More importantly, the fortification of online ER-MS and quantum structure calculation to the conventional LC–MS program is eligible to achieve unambiguous identification of isomeric metabolites. [ABSTRACT FROM AUTHOR]

In this paper, anionic branched-chain tertiary fatty alcohol sulfate surfactants were synthesized from n-hexene and n-octene using selective olefin dimerization, hydration reaction (hydroxylation), and sulfur trioxide sulfation. The direct hydration reaction of the α-olefin dimer 2-butyl-1-octene with water as a model reaction was explored for the synthesis of branched-chain tertiary fatty alcohols. Two branched-chain tertiary fatty alcohol sulfate surfactants, namely C12-SBTAS and C16-SBTAS, with different carbon chain lengths, were synthesized by the sulfur trioxide sulfation method. Their structures were confirmed by various analytical techniques, including HPLC, FT-IR, HR-MS, and 1H NMR. Equilibrium and dynamic surface tension, foaming, wetting, and emulsifying properties were compared with those of Guerbet cetyl alcohol sulfate (C16-SGAS). C12-SBTAS and C16-SBTAS exhibited good surface activity with equilibrium surface tension (γCMC) values of 27.41 mN m−1 and 26.69 mN m−1, respectively. They also had low foaming and rapid defoaming abilities, as well as good wetting and emulsifying properties, which match the application characteristics of typical branched-chain surfactants. [ABSTRACT FROM AUTHOR]

Glucosinolates (GSLs), a class of secondary metabolites found in Brassicaceae plants, play important roles in plant defense and contribute distinct flavors and aromas when used as food ingredients. Following tissue damage, GSLs undergo enzymatic hydrolysis to release bioactive volatile compounds. Understanding GSL biosynthesis and enzyme involvement is crucial for improving crop quality and advancing agriculture. Plant sulfotransferases (SOTs) play a key role in the final step of GSL biosynthesis by transferring sulfate groups to the precursor molecules. In the present study, we investigated the enzymatic reaction mechanism and broad substrate specificity of Arabidopsis thaliana sulfotransferase AtSOT16, which is involved in GSL biosynthesis, using crystal structure analysis. Our analysis revealed the specific catalytic residues involved in the sulfate transfer reaction and supported the hypothesis of a concerted acid-base catalytic mechanism. Furthermore, the docking models showed a strong correlation between the substrates with high predicted binding affinities and those experimentally reported to exhibit high activity. These findings provide valuable insights into the enzymatic reaction mechanisms and substrate specificity of GSL biosynthesis. The information obtained in this study may contribute to the development of novel strategies for manipulating GSL synthesis pathways in Brassica plants and has potential agricultural applications. • Crystal structure of Arabidopsis thaliana sulfotransferase AtSOT16 involved in glucosinolate biosynthesis is solved. • Our findings reveal the key catalytic residues responsible for sulfotransfer. • Docking simulations demonstrated a strong correlation between substrate suitability and predicted binding affinities. • These discoveries enhance knowledge of enzyme reactions and substrate selectivity in glucosinolate biosynthesis. [ABSTRACT FROM AUTHOR]

Post-translational modifications (PTMs) are ubiquitous and key to regulating protein function. Understanding the dynamics of individual PTMs and their biological roles requires robust characterisation. Mass spectrometry (MS) is the method of choice for the identification and quantification of protein modifications. This article focusses on the MS-based analysis of those covalent modifications that induce a mass shift of +80 Da, notably phosphorylation and sulfation, given the challenges associated with their discrimination and pinpointing the sites of modification on a polypeptide chain. Phosphorylation in particular is highly abundant, dynamic and can occur on numerous residues to invoke specific functions, hence robust characterisation is crucial to understanding biological relevance. Showcasing our work in the context of other developments in the field, we highlight approaches for enrichment and site localisation of phosphorylated (canonical and non-canonical) and sulfated peptides, as well as modification analysis in the context of intact proteins (top down proteomics) to explore combinatorial roles. Finally, we discuss the application of native ion-mobility MS to explore the effect of these PTMs on protein structure and ligand binding. [ABSTRACT FROM AUTHOR]

Sulfation is widespread in nature and plays an important role in modulating biological function. Among the strategies developed by microbes to access sulfated oligosaccharides as a nutrient source is the production of 6-sulfoGlcNAcases to selectively release 6-sulfoGlcNAc from target oligosaccharides. Thus far, all 6-sulfoGlcNAcases identified have belonged to the large GH20 family of ß-hexosaminidases. Here, we identify and characterize a new, highly specific non-GH20 6- sulfoGlcNAcase from Streptococcus pneumoniae TIGR4, Sp_0475 with a greater than 110,000-fold preference toward Nacetyl- ß-D-glucosamine-6-sulfate substrates over the nonsulfated version. Sp_0475 shares distant sequence homology with enzymes of GH20 and with the newly formed GH163 family. However, the sequence similarity between them is sufficiently low that Sp_0475 has been assigned as the founding member of a new glycoside hydrolase family, GH185. By combining results from site-directed mutagenesis with mechanistic studies and bioinformatics we provide insight into the substrate specificity, mechanism, and key active site residues of Sp_0475. Enzymes of the GH185 family follow a substrateassisted mechanism, consistent with their distant homology to the GH20 family, but the catalytic residues involved are quite different. Taken together, our results highlight in more detail how microbes can degrade sulfated oligosaccharides for nutrients. [ABSTRACT FROM AUTHOR]

Diverse chemical modifications fine-tune the function and metabolism of tRNA. Although tRNA modification is universal in all kingdoms of life, profiles of modifications, their functions, and physiological roles have not been elucidated in most organisms including the human pathogen, Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis. To identify physiologically important modifications, we surveyed the tRNA of Mtb, using tRNA sequencing (tRNA-seq) and genome-mining. Homology searches identified 23 candidate tRNA modifying enzymes that are predicted to create 16 tRNA modifications across all tRNA species. Reverse transcription-derived error signatures in tRNA-seq predicted the sites and presence of nine modifications. Several chemical treatments prior to tRNA-seq expanded the number of predictable modifications. Deletion of Mtb genes encoding two modifying enzymes, TruB and MnmA, eliminated their respective tRNA modifications, validating the presence of modified sites in tRNA species. Furthermore, the absence of mnmA attenuated Mtb growth in macrophages, suggesting that MnmA-dependent tRNA uridine sulfation contributes to Mtb intracellular growth. Our results lay the foundation for unveiling the roles of tRNA modifications in Mtb pathogenesis and developing new therapeutics against tuberculosis. [ABSTRACT FROM AUTHOR]

The synthesis of polysaccharide sulfates without harmful solvents used is a serious environmental problem. A method for the synthesis of xylan sulfate using the sulfamic acid–urea melt as a sulfating agent without solvents is proposed. The melt is prepared by heating the sulfamic acid–urea mixture with a molar ratio of 1 : 1 at a temperature of 110 °C. This ratio allows significant reduction of side reactions, in particular, carbamation of xylan. Sulfation is carried out at temperatures of 110,115, 120, 125, and 130 °C. The maximum yield and degree of substitution (DSsulfate 1.40) are attained at atemperature of 115 °C. The proposed method makes it possible to synthesize xylan sulfate rapidly (for 0.5 h) and without contamination of the obtained product with toxic solvents, e. g., dimethyl sulfoxide, pyridine, etc. The composition and structure of initial and sulfated xylan are confirmed by FTIR, NMR, GC, and elemental analysis. [ABSTRACT FROM AUTHOR]

Background: An essential fact underlying the severity of Staphylococcus aureus (S. aureus) infection is the bicomponent leukocidins released by the pathogen to target and lyse host phagocytes through specific binding cell membrane receptors. However, little is known about the impact of post-transcriptional modification of receptors on the leukocidin binding. Method: In this study, we used small interfering RNA library (Horizon/Dharmacon) to screen potential genes that affect leukocidin binding on receptors. The cell permeability was investigated through flow cytometry measuring the internalization of 4',6-diamidino-2-phenylindole. Expression of C5a anaphylatoxin chemotactic receptor 1 (C5aR1), sulfated C5aR1 in, and binding of 6x-His-tagged Hemolysin C (HlgC) and Panton-Valentine leukocidin (PVL) slow-component to THP-1 cell lines was detected and analyzed via flow cytometry. Bacterial burden and Survival analysis experiment was conducted in WT and myeloid TPST-cko C57BL/6N mice. Results: After short hairpin RNA (shRNA) knockdown of TPST2 gene in THP-1, HL-60, and RAW264.7, the cytotoxicity of HlgAB, HlgCB, and Panton-Valentine leukocidin on THP-1 or HL-60 cells was decreased significantly, and the cytotoxicity of HlgAB on RAW264.7 cells was also decreased significantly. Knockdown of TPST2 did not affect the C5aR1 expression but downregulated cell surface C5aR1 tyrosine sulfation on THP-1. In addition, we found that the binding of HlgC and LukS-PV on cell surface receptor C5aR1 was impaired in C5aR1+TPST2-and C5aR1-TPST2- cells. Phagocyte knockout of TPST2 protects mice from S. aureus infection and improves the survival of mice infected with S. aureus. Conclusion: These results indicate that phagocyte TPST2 mediates the bicomponent leukocidin cytotoxicity by promoting cell membrane receptor sulfation modification that facilitates its binding to leukocidin S component. [ABSTRACT FROM AUTHOR]

Hyaluronic acid (HA), also known as hyaluronan, is an anionic glycosaminoglycan widely distributed throughout various tissues of the human body. It stands out from other glycosaminoglycans as it lacks sulfation and can attain considerable size: the average human synovial HA molecule weighs about 7 million Dalton (Da), equivalent to roughly 20,000 disaccharide monomers; although some sources report a lower range of 3–4 million Da. In recent years, HA has garnered significant attention in the field of rheumatology due to its involvement in joint lubrication, cartilage maintenance, and modulation of inflammatory and/or immune responses. This review aims to provide a comprehensive overview of HA's involvement in rheumatology, covering its physiology, pharmacology, therapeutic applications, and potential future directions for enhancing patient outcomes. Nevertheless, the use of HA therapy in rheumatology remains controversial with conflicting evidence regarding its efficacy and safety. In conclusion, HA represents a promising therapeutic option to improve joint function and alleviate inflammation and pain. [ABSTRACT FROM AUTHOR]

Purpose: Despite being off-label, intravenous paracetamol (PCM) is increasingly used to control mild-to-moderate pain in preterm neonates. Here we aim to quantify the maturation of paracetamol elimination pathways in preterm neonates born below 32 weeks of gestation. Methods: Datasets after single dose (rich data) or multiple doses (sparse data) of intravenous PCM dose (median (range)) 9 (3–25) mg/kg were pooled, containing 534 plasma and 44 urine samples of PCM and metabolites (PCM–glucuronide, PCM–sulfate, PCM–cysteine, and PCM–mercapturate) from 143 preterm neonates (gestational age 27.7 (24.0–31.9) weeks, birthweight 985 (462–1,925) g, postnatal age (PNA) 5 (0–30) days, current weight 1,012 (462–1,959) g. Population pharmacokinetic analysis was performed using NONMEM® 7.4. Results: For a typical preterm neonate (birthweight 985 g; PNA 5 days), PCM clearance was 0.137 L/h, with glucuronidation, sulfation, oxidation and unchanged renal clearance accounting for 5.3%, 73.7%, 16.3% and 4.6%, respectively. Maturational changes in total PCM clearance and its elimination pathways were best described by birthweight and PNA. Between 500–1,500 g birthweight, total PCM clearance increases by 169%, with glucuronidation, sulfation and oxidation clearance increasing by 347%, 164% and 164%. From 1–30 days PNA for 985 g birthweight neonate, total PCM clearance increases by 167%, with clearance via glucuronidation and oxidation increasing by 551%, and sulfation by 69%. Conclusion: Birthweight and PNA are the most important predictors for maturational changes in paracetamol clearance and its glucuronidation, sulfation and oxidation. As a result, dosing based on bodyweight alone will not lead to consistent paracetamol concentrations among preterm neonates. [ABSTRACT FROM AUTHOR]