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Simultaneous detection of multiple amino acids (AAs) instead of individual AAs is inherently worthwhile for improving diagnostic accuracy in clinical applications. Here, a facile and reliable colorimetric microfluidic paper-based analytical device (μPAD) using carbon dots doped with transition metals (Cr3+, Mn2+, Fe3+, Co2+, Ni2+, Cu2+, and Zn2+) has been provided to detect and discriminate 20 natural amino acids. To make the colourless metal-doped carbon dots suitable for colorimetric assays, they were mixed with ninhydrin to form a charge transfer complex. This optical tongue system, which was constructed by dropping mixtures of ninhydrin with a series of metal-doped carbon dots on a paper substrate in an array format, represented obvious but different colorimetric signatures for every examined amino acid. Since bovine serum albumin was used as a chiral selector reagent for synthesizing the CDs, the sensor device represented excellent selectivity to identify enantiomeric species of AAs. This is the first optical array device that can simultaneously discriminate AAs and several of their enantiomers. We employed various statistical and chemometric methods to analyze the digital data library collected by Image J software, including principal component analysis (PCA), linear discriminant analysis (LDA), and hierarchical cluster analysis (HCA). Twenty AAs could be well distinguished at various concentrations (10.00, 5.00, 2.50, and 1.25 mM). The colorimetric patterns were highly repeatable and were characteristic of individual AAs. Besides qualitative analysis, the designed μPAD-based optical tongue represented quantitative analysis ability, e.g., for lysine in the concentration ranges of 0.005–20.0 mM with a detection limit of 1.0 × 10−6 M and for arginine in the concentration range of 0.12–20.00 mM with a detection limit of 80.0 × 10−6 M. In addition, the binary, ternary, and quaternary mixtures of AAs could also be well recognized with this sensor. [ABSTRACT FROM AUTHOR]

“The best catalyst is no catalyst.” With growing public concern over global warming and the amount of greenhouse gases, it is important to reduce the amount of chemicals and eliminate waste, to obtain better results in a simple, selective, safe, and environmentally benign fashion compared to conventional tedious chemical synthesis. Herein, we disclose an environmentally benign, rapid, catalyst/promoter/coupling reagent-free cyclization procedure of free amino acids to furnish exclusively cyclic dipeptides (2,5-diketopiperazines, DKPs) in excellent or even quantitative yield, along with their solid state self-assembling properties. This process is extremely simple and highly efficient with little or no traditional synthetic skills and without any chromatographic purification. Synthesis of structurally diverse DKPs has been achieved with a dramatic decrease in the reaction time, the amount/number of solvents used, a significant increase in the yield and nearly complete elimination of waste. As a result, this is an excellent example for the environmentally benign, clean and green chemistry concept. The most exciting outcome of our investigation is an unusual case of chiral self-recognition encountered upon the cyclization of rac-pipecolic acid, which resulted in the formation of the meso-product exclusively. [ABSTRACT FROM AUTHOR]

Ankylosing spondylitis (AS) is a chronic inflammatory arthritis that predominantly affects the axial skeleton in adolescent patients. The natural history of the disease remains poorly characterized. In this study, we combined GC–MS and LC–MS techniques to evaluate the major metabolic changes in the plasma of AS patients in view of metabonomics. Univariate and multivariate analysis were employed for altered metabolite comparison and pattern recognition. Application of supervised partial least-squares discrminant analysis to either GC–MS or LC–MS data allowed accurate discrimination of AS patients from normal controls, demonstrating its potential diagnostic utilization. In addition, AS patients presented elevated plasma concentrations of proline, glucose, phosphate, urea, glycerol, phenylalanine and homocysteine but reduced levels of phosphocholines, tryptophan and a bipeptide – phenylalanyl-phenylalanine. In the context of their involved metabolic pathways, the identified metabolites were discussed accordingly. This investigation primarily proved that integrated chromatography–mass spectrometry and integrated uni- and multi-variate statistical analysis facilitated metabonomics to be a more promising tool in disease research. [ABSTRACT FROM AUTHOR]

Protein phosphorylation plays an important role in many significant cellular processes, and has thus gained tremendous interest in the field of proteomics. The electro-active tyrosine residue, as an important receptor of phosphorylation in proteins, exhibits electro-inactivity after being phosphorylated on the hydroxy group of its aromatic ring. In this study, the electrochemical oxidation of tyrosine on indium tin oxide (ITO) electrodes was catalyzed with an electron mediator Os(bpy)32+(bpy = 2,2′-bipyridine) and was employed as a signal reporter to differentially detect non-phosphorylated and phosphorylated peptides. A short, tyrosine-containing peptide glu-glu-glu-glu-glu-tyr (EY-6) was immobilized on an ITO surface using the layer-by-layer self-assembly method, and was detected by cyclic voltammetry in an Os(bpy)32+solution. The limit of detection was about 0.23 μg mL−1EY-6 in solution. The phosphorylated peptide glu-glu-glu-glu-glu-tyr-OP (EY-6P) did not produce an appreciable oxidation current on the electrode. Surface plasmon resonance measurements revealed that the amount of EY-6 and EY-6P adsorbed on the sensor chip surface was 269 and 378 pg mm−2, respectively. The poly(glu, tyr) (4 : 1) peptide, a protein tyrosine kinase substrate, was also detected by the same approach, with a detection limit of 0.65 μg mL−1. This new approach offers the possibility of label-free and on-chip detection of protein tyrosine kinase activity. [ABSTRACT FROM AUTHOR]

We describe the synthesis of homo-, block, and clickable copolypeptide brushes from low surface area substrates using nickel-mediated surface-initiated polymerization of α-amino N-carboxyanhydrides. [ABSTRACT FROM AUTHOR]

4-Substituted oxazolines, which are readily synthesized from naturally occurring α-amino acids, are converted efficiently and stereospecifically to β-amidoaldehydes in the presence of synthesis gas and catalytic dicobalt octacarbonyl. [ABSTRACT FROM AUTHOR]

Achiral meteoritic amino acids, glycine and α-methylalanine, with hydrogen isotope (D/H) chirality, acted as the source of chirality in asymmetric autocatalysis with amplification of ee to afford highly enantioenriched 5-pyrimidyl alkanols. [ABSTRACT FROM AUTHOR]

In this paper, a novel fluorescent probe, TPA-PAT, with continuous recognition based on triphenylamine was designed, synthesized, and characterized by NMR, IR, and fluorescence spectrophotometry techniques. The research results showed that the probe could specifically recognize Cu2+ in DMSO/H2O (99:1, v/v) with a detection limit as low as 0.40 mM and a coordination ratio of 1: 2. On this basis, it was found that its complex TPA-PAT-Cu2+ could achieve a continuous progressive recognition of the anion S2- and amino acids GSH, L-His, and L-Gly, while simultaneously showing high sensitivity for them with low detection limits of 25.7, 18.9, 21.7, and 45.9 nM, respectively. The probe had good reversibility and could be recycled. In addition, the probe TPA-PAT could simultaneously recognize Cu2+ and Hg2+ in acetone/H2O (99:1, v/v) with detection limits of 0.16 and 0.20 mM, respectively, while their coordination ratios were 1: 2. Similarly, its complex TPA-PAT-Hg2+ was able to continuously recognize the amino acids Cys and GSH with detection limits of 0.34 and 0.29 mM, respectively. It was also found that the probe and its complexes were able to be prepared for convenient dipstick applications, which could achieve a rapid fluorescence response to anions and amino acids and suggested its very good application prospects. [ABSTRACT FROM AUTHOR]

Copper complexes are considered as potential candidates for anticancer therapy and medical applications. In this paper, three new Cu(II) complexes, [Cu(IPY)2](ClO4)2·H2O (CuI1), [Cu(IPY)(L -Phe)H2O]ClO4·0.5H2O (CuI2) and [Cu(IPY)(L -Val)H2O]ClO4 (CuI3) (where IPY = 2-(1H-imidazol-2-yl)pyridine, L -Phe = L -phenylalanine, and L -Val = L -valine), with good amphipathic properties were synthesized and characterized. Their single crystal X-ray diffraction results revealed that CuI1 was four-coordinated, while CuI2 and CuI3 both adopted a five-coordinated tetragonal pyramidal configuration. Multi-spectral methods, viscosity experiment and molecular docking technique showed that the three complexes interacted with DNA through insertion. The results of the gel electrophoresis experiments indicated that DNA was oxidatively cleaved by all the complexes in a concentration-dependent manner. Moreover, singlet oxygen (1O2), hydrogen peroxide (H2O2) and superoxide anion radicals (˙O2−) were associated with the oxidative cleavage of DNA. All the complexes also had good binding affinity with human serum albumin (HSA). The MB degradation assay revealed that all complexes could react with H2O2 to form ˙OH through Fenton-like processes. The complexes displayed good antiproliferative activity against the tested human cancer cells in vitro, including cervical carcinoma cells (HeLa), liver cancer cells (HepG2 and BEL-7402) and gastric adenocarcinoma cells (SGC-7901), but showed lower toxicity to normal liver cells (LO2). The anticancer mechanism research revealed that CuI1, CuI2 and CuI3 arrested the cell cycle at the S phase, elevated intracellular reactive oxygen species (ROS) levels and induced loss of mitochondrial membrane potential (MMP). The results indicated that these Cu(II) complexes could induce DNA damage and ROS-mediated mitochondrial dysfunction, leading to cancer cell apoptosis. Our work provides a theoretical basis for the design of new low-toxicity and highly efficient anticancer Cu(II) complexes by incorporating biological metabolites and aromatic heterocyclic ligands. [ABSTRACT FROM AUTHOR]

Covering: up to October 2020 Furanocoumarins are plant secondary metabolites used to treat several skin disorders, such as psoriasis and vitiligo, and also with other potential therapeutic activities. Furanocoumarins are extracted from plants where they accumulate in low amounts over long growth periods. In addition, their extraction and purification are difficult in an environmentally unfriendly and expensive process. Hence, new sustainable and greener production schemes able to overcome such limitations ought to be developed. While the heterologous production of simple coumarins has been demonstrated, the biosynthesis of more complex furanocoumarins remains greatly unexplored. Although several important steps of the pathway have been elucidated in the last decade, the complete pathway has not been completely unravelled. In this paper, we review the natural conversion of amino acids into furanocoumarins, as well as the heterologous expression of each enzyme of the pathway. We also explore the challenges that need to be addressed so that their heterologous production can become a viable alternative. [ABSTRACT FROM AUTHOR]

Samarium macrocycle-based complex Sm-2n, a luminescent matrix bearing two dynamic imine bonds as recognition sites and a Sm(III) emitter as the fluorescence indicator, can selectively probe cysteine over other analogous amino acids and show remarkable turn-off fluorescent character. Moreover, using Sm-2n-impregnated paper-based test strips and RGB outputs, we develop a smartphone-based analysis method to give a convenient approach with satisfactory results for cysteine detection and determination. [ABSTRACT FROM AUTHOR]

A new benzothiazole azo dye [(E)-1-((6-methoxybenzo[d]thiazole-2-yl)diazenyl)naphthalene-2,6-diol] (also known as “BAN”), has been synthesised and used as a chemosensor for the rapid and selective detection of mercury(ii) ions in water. The pink coloured chemosensor turns blue when reacted with mercury(ii) ions due to the formation of a 2 : 1 coordination complex. The complex formation causes a bathochromic shift of the chemosensor's UV absorption peak from 540 to 585 nm and turns on a highly selective fluorescence emission at 425 nm. The change in the optical property of BAN upon complexation with mercury(ii) was confirmed by ab initio calculations. The new chemosensor was used to quantify mercury(ii) ions in water by fluorescence spectroscopy down to 5 × 10−8 M (10 ppb). The limit of detection (LOD) of Hg2+ was 9.45 nM (1.8 ppb) which satisfies the maximum allowable Hg2+ concentration in drinking water that is set by the WHO. The BAN–Hg(ii) complex was used for the determination of cysteine (Cys) in aqueous solution by UV-Vis spectroscopy down to 1 × 10−7 M. The thiol-containing amino acid preferentially coordinates the mercury ions of the BAN–Hg(ii) complex. This causes dissociation of the blue-coloured complex and the liberation of the pink-coloured BAN dye. The colour change of the BAN–Hg(ii) complex from blue to pink was selective to the Cys biothiol while other non-thiol containing amino acids did not cause a colour change. For the in-field application, filter paper strips were loaded with the BAN–Hg(ii) complex and used as a disposable sensor for the detection of cysteine (Cys) by the naked eye. Therefore, the BAN chemosensor offers a sensitive, and rapid tool for the detection of mercury(ii) in water. In addition, the BAN–Hg(ii) complex can be used as a simple and selective chemosensor of the screening of purified biothiols, such cysetine, homocysteine and glutathione in biology research and pharmaceutical/food industries. [ABSTRACT FROM AUTHOR]

This is the tenth Atomic Spectrometry Update (ASU) to focus on advances in elemental speciation and covers a period of approximately 12 months from December 2016. This ASU review deals with all aspects of the analytical atomic spectrometry speciation methods developed for: the determination of oxidation states; organometallic compounds; coordination compounds; metal and heteroatom-containing biomolecules, including metalloproteins, proteins, peptides and amino acids; and the use of metal-tagging to facilitate detection via atomic spectrometry. The review does not cover fractionation, which is sometimes termed operationally defined speciation. As with all ASU reviews the focus of the research reviewed includes those methods that incorporate atomic spectrometry as the measurement technique. However, because speciation analysis is inherently focused on the relationship between the metal(loid) atom and the organic moiety it is bound to, or incorporated within, atomic spectrometry alone cannot be the sole analytical approach of interest. For this reason molecular detection techniques are also included where they have provided a complementary approach to speciation analysis. As in previous years, As speciation continues to dominate the current literature with a significant number of publications concerning Hg and Se speciation and ‘biomolecules’, in which category a number of papers covered in the Se section could also belong. The number of elements covered in these updates also continues to rise with speciation analysis of over 20 elements reported this year. [ABSTRACT FROM AUTHOR]

In this paper we reported the synthesis and the in vitro and the in vivo biological evaluation of linear pseudo-peptides incorporating the N-VGCC blocker tripeptide Phe-NMe-Leu-Tyr(OBz)-NtBu and the biphalin pharmacophore Tyr-d-Ala-Gly-Phe. The novel sequences have been designed by using amino acids of different length to join the two pharmacophores and explore the structure–activity relationships of the novel compounds. [ABSTRACT FROM AUTHOR]

This paper describes the consequences of incorporating a constrained heterocyclic aromatic β-amino acid 3-aminothiophenecarboxylic acid (3-Atc) into peptides containing β-turn forming elements such as Pro-Gly motif and the effect on the secondary structural architecture of the entire peptide backbone. Conformational investigations of oligomers comprising an α,β,α peptide sequence were carried out by single-crystal X-ray diffraction, solution-state NMR, nOe-restrained MD simulation and circular dichroism studies. The results suggested that these peptide sequences assume helical architecture. The helical folding in the oligomers was found to be devoid of inter-residual H-bonding, instead found to be stabilized by a co-operative effect of 6-membered H-bonding within the 3-Atc unit and conformational restrictions of individual amino acids in the peptide backbone. [ABSTRACT FROM AUTHOR]

The present paper reports the one-pot synthesis of N-doped graphene–Ag nanocomposites (N-GrAg) involving the in situ generation of Ag nanoparticles (NPs). The simultaneous reduction of GO and Ag+ to produce N-GrAg has been achieved under mild reaction conditions using an environmentally benign reducing agent, glycine, in aqueous medium without adding any external stabilizer. XRD and SAED analyses revealed the presence of Ag in the fcc structure. HRTEM analysis shows a ‘d’ spacing of 0.236 nm corresponding to the highest intensity (111) reflection of Ag which matches the fcc structure. The N-doping of graphene and its uniform decoration by Ag NPs (with an av. dia. of 17.5 nm) having a relatively low surface atomic % of Ag (0.309) are evidenced by TEM and XPS analyses. Raman spectroscopy has also revealed that the decoration of N-Gr with Ag NPs resulted in the enhancement of the D and G bands by about 365%. The presence of Ag in N-GrAg prevents the folding of the graphene sheet as was revealed by TEM analysis. The supramolecular interactions of Ag with different moieties of N in N-GrAg were evidenced by IR, 13C NMR and XPS analyses, which resulted in the enhancement of its surface area and electrical conductivity as compared to that of N-Gr. The presence of Ag NPs on N-Gr increased the current response in cyclic voltammetry by more than seven fold as compared to that of N-Gr. These nanocomposites exhibited a fairly high SERS activity for 4-aminothiophenol, employed as the probe molecule, and allowed its detection at a 50 nM concentration even for the fairly small sized Ag NPs used in the present work. [ABSTRACT FROM AUTHOR]

In this paper, we report a novel sample introduction and chemical reaction strategy by drop-by-drop inkjet injection for an electrophoretically mediated microanalysis (EMMA). This method makes it possible to achieve an on-line introduction of reactant solutions by alternately ejecting small plugs, with an overlapping region of the plugs for mixing the reactants by electrophoresis, supporting chemical reactions, followed by electrophoretic separation of the final compounds. As a proof-of-concept of the method, the EMMA of an inkjetted mixture of 4-fluoro-7-nitrobenzofurazan (NBD-F) and amino acids was carried out as a model chemical reaction. The product NBD-amino acids were quantified by detection with laser induced fluorescence. The optimal conditions for the procedure were: inkjet driving voltage: +40–44 V; pulse width: 20–24 μs; drop-by-drop injection of reactant solutions: alternately 2 drops × 25 times for the amino acid solution and the NBD-F solution; zone overlapping voltage and time: 3 kV and 2 s; incubation time after overlapping: 5 min; separation voltage: 18 kV. Under the optimized conditions, a significant enhancement in sensitivity and a sensitive quantitative analysis were realized. The results obtained were comparable with those using the off-line labeling method. This method is rapid, cost-effective, and readily automated for EMMA. [ABSTRACT FROM AUTHOR]

In this paper the reactivity of K15H[Zr(α2-P2W17O61)2]·25H2O (1), a Zr(iv)-substituted Wells–Dawson polyoxometalate, is examined towards a series of Gly–Aa, Aa–Gly or Aa–Ser dipeptides, in which the nature and the size of the Aa amino acid side chain were varied. The rate of peptide bond hydrolysis, determined by 1H NMR experiments, in Gly–Aa dipeptides is strongly dependent on the molecular volume and the chemical structure of the Aa side chain. When the volume of the aliphatic side chain of the Aa residue in Gly–Aa increased, a clear decrease in the hydrolysis rate was observed. Replacing one α-H in the C-terminal Gly residue of Gly–Gly by a methyl group (Gly–Ala) resulted in a 6-fold reactivity decrease, pointing towards the importance of steric factors for efficient peptide bond hydrolysis. The rate constants for peptide bond hydrolysis in Gly–Aa dipeptides at pD 5.0 and 60 °C ranged from 208.0 ± 15.6 × 10−6 min−1 for Gly–Ser to 5.0 ± 1.0 × 10−6 min−1 for Gly–Glu, reflecting the influence of the different nature of the amino acid side chains on the hydrolysis rate. Faster hydrolysis was observed for peptides containing Ser and Thr since the hydroxyl group in their side chain is able to facilitate amide bond hydrolysis by promoting an N→O acyl rearrangement. Peptides containing positively charged side chains at pD 5.0 show enhanced hydrolysis rates as a result of the secondary electrostatic interactions with the negatively charged surface of the polyoxometalate, which stabilize the peptide–polyoxometalate complex. A slow hydrolysis rate was observed for Gly–Glu, because of the preferential coordination of the carboxylate group in the side chain of Glu to Zr(iv), which prevents coordination of the peptide carbonyl group and its activation towards hydrolysis. [ABSTRACT FROM AUTHOR]

This paper demonstrates that the combination of simultaneous measurements of 12C+ and 13C+ ion currents by MC-ICPMS and calibration based on the use of gravimetrically prepared synthetic isotope mixtures provides a unique possibility for accurate determination of absolute 13C/12C isotope amount ratios which are metrologically traceable to the SI units. We have applied this approach to the determination of 13C/12C isotope amount ratios in glycine – an amino acid of importance in a variety of applications, including paleoecological studies and food security analysis. Eleven synthetic isotope mixtures with different n(13C)/n(12C) isotope amount ratios were prepared by gravimetric weighing and mixing of two well-characterized parent glycines, each highly enriched in either 12C or 13C isotopes. The parent materials were dissolved in dilute nitric acid and mixed as solutions. In measurements of the 13C/12C isotope ratio in aqueous solutions it was found essential to account for the relatively high procedural blank and for spectral interference of 12C1H+ ions in 13C+ ion current. The former is due to dissolution of atmospheric CO2 gas and presence of non-ionic organic contaminants even in high purity water. An improved measurement protocol was used in this study to address the above features. It involved performing 13C/12C isotope ratio measurements in high resolution mode of MC-ICPMS to completely resolve the spectral interference in 13C+ ion current and keeping elevated concentrations of carbon (∼0.5%) in the measured samples to minimize contribution of the blank. A value of the 13C/12C isotope amount ratio of 0.010648 ± 0.000042 (expanded uncertainty, k = 2) was obtained for the glycine candidate reference material in 12 measurement sessions with independently prepared calibration mixtures. This work shows excellent agreement between the iteration procedure and analytical solution which were used for the calculation of the calibration factor K. It also demonstrates that possible non-linearity between measured ion currents and isotope amount fractions has an insignificant effect on the accuracy of 13C/12C isotope amount ratio measurements of natural glycine. [ABSTRACT FROM AUTHOR]

Oils, fats, carbohydrates, lignin, and amino acids are all important raw materials for the production of biorenewables. These compounds already play an important role in everyday life in the form of wood, fabrics, starch, paper and rubber. Enzymatic reactions do, in principle, allow the transformation of these raw materials into biorenewables under mild and sustainable conditions. There are a few examples of processes using immobilised enzymes that are already applied on an industrial scale, such as the production of High-Fructose Corn Syrup, but these are still rather rare. Fortunately, there is a rapid expansion in the research efforts that try to improve this, driven by a combination of economic and ecological reasons. This review focusses on those efforts, by looking at attempts to use fatty acids, carbohydrates, proteins and lignin (and their building blocks), as substrates in the synthesis of biorenewables using immobilised enzymes. Therefore, many examples (390 references) from the recent literature are discussed, in which we look both at the specific reactions as well as to the methods of immobilisation of the enzymes, as the latter are shown to be a crucial factor with respect to stability and reuse. The applications of the renewables produced in this way range from building blocks for the pharmaceutical and polymer industry, transport fuels, to additives for the food industry. A critical evaluation of the relevant factors that need to be improved for large-scale use of these examples is presented in the outlook of this review. [ABSTRACT FROM AUTHOR]

This paper describes an original methodology for peptide bond synthesis avoiding toxic solvents and reactants. Ball-milling stoichiometric amounts of Boc-protected α-amino acid N-carboxyanhydrides (Boc-AA-NCA) or Boc-protected α-amino acid N-hydroxysuccinimide esters (Boc-AA-OSu) with α-amino acid alkyl ester salts in the presence of NaHCO3 and a minimal quantity of EtOAc led to the production of di- to pentapeptides in an efficient and environmentally benign manner. This approach was successfully applied to the synthesis of Leu-enkephalin. [ABSTRACT FROM AUTHOR]

Earlier we reported the tendency of ferrocenylmethyl substituted amino acids to organize around Cu(ii) in a C2symmetry. In this paper we have utilized this property to form a chiral cavity using a l-tyrosine derivative. Structural characterization of [CuII(S-fTyr)2(MeCN)2] (1), where S-fTyr1−is ferrocenylmethyl-l-tyrosinate, showed that the alignment of two tyrosine aromatic rings around the fifth coordination site generates a narrow cavity. Structural characterization of [Cu(S-fTyr)2(pyrazine)] (2), [Cu(S-fTyr)2(pyridine)] (3), [Cu(S-fTyr)2(bpy)] (4) and [Cu(S-fTyr)2(H2O)] (5) revealed that planar heterocyclic N-donors as guests stabilized the cavity, while polar water molecules destroyed it. Electrochemical properties of the complexes showed a shift of CuII/CuIpotentials depending on the strength of the guest binding inside the cavity. [ABSTRACT FROM AUTHOR]

This paper reports on the synthesis, characterization and electrochemical properties of four ferrocenylmethyl substituted l-amino acid ligands and their Cu(ii) complexes. Structural characterization of the complexes of l-methionine and l-asparagine derived ligands showed axial coordination of weak thioether and amide respectively to Cu(ii). Coordination of the thioether group of l-methionine to copper (2.791 Å) is shorter than observed in the electron transfer protein plastocyanin (2.9 Å). Methionine thioether does not bind in synthetic Cu(ii) complexes. The characterization of bis-complexes (metal : ligand ratio 1 : 2) with l-serine and l-threonine derivatives showed axial coordination of water with a shorter Cu–O bond length compared to that observed in the corresponding amino acid complexes. The structures also revealed separation of the hydrophilic and hydrophobic regions due to amino acid and ferrocene respectively which resulted in the formation of interesting H-bonded networks. [ABSTRACT FROM AUTHOR]

This paper discusses the design of a colorimetric sensor for chiral detection of histidine (His) based on silver nanoparticle clusters. It shows highly selective and sensitive recognition towards l-His via amplifying the chiral signal by the formed clusters. [ABSTRACT FROM AUTHOR]

A series of room temperature ionic liquids (ILs), in which cholinium acts as the cation and amino acids as the anions, were prepared via a simple and green chemical route, and characterized. Most of the ILs dissolved lignin efficiently and selectively (with solubilities of 140–220 mg of lignin per g of IL). The solubility of xylan in these ILs (which ranged from ＜1 to 85 mg g−1) depended on the nature of the anion, while cellulose was scarcely soluble (＜5 mg g−1). In addition, enzymatic hydrolysis of microcrystalline cellulose and rice straw was enhanced significantly after pretreatment using the IL [Ch][Gly]. [ABSTRACT FROM AUTHOR]