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Collective behavior has become a recent topic of investigation in systems chemistry. In pursuing this phenomenon, we present polymersome stomatocytes loaded with the enzyme urease, which show basic stigmergy-based communication and are capable of signal production, reception, and response by clustering with surface complementary binding partners. The collective behavior is transient and based on the widely known pH-sensitive non-covalent interactions between nitrilotriacetic acid (NTA) and histidine (His) moieties attached to the surface of urease-loaded and empty stomacytes, respectively. Upon the addition of the substrate urea, the urease stomatocytes are able to increase the environmental pH, allowing the NTA units to interact with the surface histidines on the complementary species, triggering the formation of transient clusters. The stomatocytes display a maximum clustering interaction at a pH between 6.3 and 7.3, and interparticle repulsive behavior outside this range. This leads to oscillating behavior, as the aggregates disassemble when the pH increases due to high local urease activity. After bulk pH conditions are restored, clustering can take place again. Within the detectable region of dynamic light scattering, individual stomatocytes can aggregate to agglomerates with 10 times their volume. Understanding and designing population behavior of active colloids can facilitate the execution of cooperative tasks, which are not feasible for individual colloids.

Urease is a metalloenzyme that contains two Ni(II) ions in its active site and catalyzes the hydrolysis of urea into ammonia and carbon dioxide. The development of effective urease inhibitors is crucial not only for mitigating nitrogen losses in agriculture but also for offering an alternative treatment against infections caused by resistant pathogens that utilize urease as a virulence factor. This study focuses on synthesizing and investigating the urease inhibition potential of Biginelli Adducts bearing a boric acid group. An unsubstituted or hydroxy-substituted boronic group in the Biginelli adducts structure enhances the urease inhibitory activity. Biophysical and kinetics studies revealed that the best Biginelli adduct (4e; IC 50  = 132 ± 12 µmol/L) is a mixed inhibitor with higher affinity to the urease active site over an allosteric one. Docking studies confirm the interactions of 4e with residues essential for urease activity and demonstrate its potential to coordinate with the nickel atoms through the oxygen atoms of carbonyl or boronic acid groups. Overall, the Biginelli adduct 4e shows great potential as an additive for developing enhanced efficiency fertilizers and/or for medical applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Inc.)

Urinary tract infection caused by Klebsiella, Proteus and Streptococcus is a urease dependent process, hence treatment of these infections by antibacterial compounds lies in inhibition of their virulence factors. The crude methanolic extracts derived from sumac fruit, pomegranate peel and Indian almond leaves were separated into anthocyanin and non-anthocyanin fractions using solid phase cartridges. The inhibitory effect of these fractions was determined on the growth of urease producing species and jack bean urease activity. Known compounds in the fractions were also docked with ureases of different biological origins viz. K. pneumoniae (PDB ID: 8HCN), K. aerogenes (PDB ID: 2KAU), Helicobacter pylori (PDB ID:8HC1)and Canavalia ensiformis (jack bean) (PDB ID: 3LA4) to determine their binding affinities and interaction with the enzyme. All the fractions showed significant inhibition growth for P. mirabilis, S. epidermidis and K.pneumoniae. Among the samples, sumac showed greatest inhibition against all (MIC 6-25 mg.mL -1 ) while among the fractions, anthocyanin was found to be most active (MIC 6-12 mg/mL). Likewise, all fractions inhibited urease with lowest ICs 50 shown by sumac fractions (21-116 μg.mL -1 ). Out of 39 compounds docked, 27 showed interaction with movable flaps and/or active site of ureases which explains their mode of inhibition., Competing Interests: Declaration of competing interest This is to be certified that there is no conflict of interest in the submission of research paper entitled “Inhibitory Effect of Polyphenols from Sumac, Pomegranate and Indian Almond on Urease Producing Bacteria and Jack Bean Urease Activity.”, (Copyright © 2024 Elsevier B.V. All rights reserved.)

Thirteen novel hydrazone-Schiff bases (3-15) of fexofenadine were succesfully synthesized, structurally deduced and finally assessed their capability to inhibit urease enzyme (in vitro). In the series, six compounds 12 (IC 50 =10.19±0.16 μM), 11 (IC 50 =15.05±1.11 μM), 10 (IC 50 =17.01±1.23 μM), 9 (IC 50 =17.22±0.81 μM), 13 (IC 50 =19.31±0.18 μM), and 14 (IC 50 =19.62±0.21 μM) displayed strong inhibitory action better than the standard thiourea (IC 50 =21.14±0.24 μM), while the remaining compounds displayed significant to less inhibition. LUMO and HOMO showed the transferring of charges from molecules to biological transfer and MEP map showed the chemically reactive zone appropriate for drug action are calculated using DFT. AIM charges, non-bonding orbitals, and ELF are also computed. The urease protein binding analysis benefited from the docking studies., (© 2024 Wiley-VHCA AG, Zurich, Switzerland.)

Urease inhibitors can inhibit the decomposition rate of urea, and decrease the air pollution caused by ammonia. In this paper, four new copper(II) complexes [CuL(ONO2)]n (1), [Cu2L2(μ1,3-N3)2] (2), [CuBrL] (3), and [CuClL] (4), where L = 5-bromo-2-(((2-methylamino)ethyl)imino)methyl)phenolate, have been synthesized and characterized. The complexes were characterized by elemental analyses, IR and UV-Vis spectroscopy, molar conductivity, and single crystal X-ray diffraction. X-ray analysis reveals that Cu atoms in complexes 1 and 2 are in square pyramidal coordination, and those in complexes 3 and 4 are in square planar coordination. The molecules of the complexes are linked through hydrogen bonds and π···π interactions. The inhibitory effects of the complexes on Jack bean urease were studied, which showed that the complexes have effective activity on urease.

A new dinuclear copper(II) complex [Cu2(μ-Br)2L2]·0.5MeOH with the benzohydrazone ligand 4-bromo-N'-(1-(pyridin-2-yl)ethylidene)benzohydrazide (HL) has been synthesized and characterized by elemental analysis, IR and UV-Vis spectroscopic studies. Single crystal structures of the complex and the benzohydrazone compound were studied. The Cu atoms in the complex are coordinated by two benzohydrazone ligands and two Br bridging groups, forming square pyramidal coordination. The complex has good inhibitory activity on Jack bean urease, with IC50 value of 1.38 μmol·L-1.

This study reports the green synthesis and urease inhibitory activities of Ag and Au nanoparticles (NPs) using Crataegus oxyacantha extract. The synthesized NPs were characterized by UV-visible, FT-IR spectroscopy, atomic force microscopy, and scanning electron microscopy. The obtained NPs were spherical in shape, and their size was around 85 nm. A strong correlation between the phytochemicals present in the extract and their capability for the synthesis of NPs was observed. Furthermore, the shape, size, stability, and bioactivity of the NPs were strongly influenced by the stabilizing phytochemicals. The experimental analysis suggested that these NPs have substantial stability in a diverse range of physiological conditions such as pH, salinity, and temperature. The NPs exhibited potent urease enzyme inhibitory activities with percent inhibition of 99.25 and IC 50 value of 1.38 ± 0.3, comparable to the standard (thiourea percent inhibition, that is, 98.2% and IC 50 value 5.3 ± 0.04). These results suggested that the proposed NPs could be used in the homeopathic and pharmaceutical industries for biomedical applications., (© 2020 International Union of Biochemistry and Molecular Biology, Inc.)

Among carbohydrate-processing enzymes, Jack bean α-mannosidase (JBα-man) is the glycosidase with the best responsiveness to the multivalent presentation of iminosugar inhitopes. We report, in this work, the preparation of water dispersible gold nanoparticles simultaneously coated with the iminosugar deoxynojirimycin (DNJ) inhitope and simple monosaccharides (β-d-gluco- or α-d-mannosides). The display of DNJ at the gold surface has been modulated (i) by using an amphiphilic linker longer than the aliphatic chain used for the monosaccharides and (ii) by presenting the inhitope, not only in monomeric form, but also in a trimeric fashion through combination of a dendron approach with glyconanotechnology. The latter strategy resulted in a strong enhancement of the inhibitory activity towards JBα-man, with a K i in the nanomolar range ( K i = 84 nM), i.e., more than three orders of magnitude higher than the monovalent reference compound.

Over 30 years ago, an intriguing posttranslational modification was found responsible for creating concanavalin A (conA), a carbohydrate-binding protein from jack bean (Canavalia ensiformis) seeds and a common carbohydrate chromatography reagent. ConA biosynthesis involves what was then an unprecedented rearrangement in amino-acid sequence, whereby the N-terminal half of the gene-encoded conA precursor (pro-conA) is swapped to become the C-terminal half of conA. Asparaginyl endopeptidase (AEP) was shown to be involved, but its mechanism was not fully elucidated. To understand the structural basis and consequences of circular permutation, we generated recombinant jack bean pro-conA plus jack bean AEP (CeAEP1) and solved crystal structures for each to 2.1 and 2.7 Å, respectively. By reconstituting conA biosynthesis in vitro, we prove CeAEP1 alone can perform both cleavage and cleavage-coupled transpeptidation to form conA. CeAEP1 structural analysis reveals how it is capable of carrying out both reactions. Biophysical assays illustrated that pro-conA is less stable than conA. This observation was explained by fewer intermolecular interactions between subunits in the pro-conA crystal structure and consistent with a difference in the prevalence for tetramerization in solution. These findings elucidate the consequences of circular permutation in the only posttranslation example known to occur in nature., (© American Society of Plant Biologists 2021. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Enzymes immobilized on a nano-structured surface were used to switch the activity of one enzyme by a local pH change produced by another enzyme. Immobilized amyloglucosidase (AMG) and trypsin were studied as examples of the pH-dependent switchable "target enzymes." The reactions catalyzed by co-immobilized urease or esterase were increasing or decreasing the local pH, respectively, thus operating as "actuator enzymes." Both kinds of the enzymes, producing local pH changes and changing biocatalytic activity with the pH variation, were orthogonal in terms of the biocatalytic reactions; however, their operation was coupled with the local pH produced near the surface with the immobilized enzymes. The "target enzymes" (AMG and trypsin) were changed reversibly between the active and inactive states by applying input signals (urea or ester, substrates for the urease or esterase operating as the "actuator enzymes") and washing them out with a new portion of the background solution. The developed approach can potentially lead to switchable operation of several enzymes, while some of them are inhibited when the others are activated upon receiving external signals processed by the "actuator enzymes." More complex systems with branched biocatalytic cascades can be controlled by orthogonal biocatalytic reactions activating selected pathways and changing the final output.

Soft metal ions can inactivate urease, a Ni(II)-dependent enzyme whose hydrolytic activity has significant implications in agro-environmental science and human health. Kinetic and structural studies of the reaction of Canavalia ensiformis urease (JBU) and Sporosarcina pasteurii urease (SPU) with Ag(I) compounds of general formula [Ag(PEt 3 )X] 4 (X = Cl, Br, I), and with the ionic species [Ag(PEt 3 ) 2 ]NO 3 , revealed the role of the Ag(I) ion and its ligands in modulating the metal-enzyme interaction. The activity of JBU is obliterated by the [Ag(PEt 3 )X] 4 complexes, with IC 50 values in the nanomolar range; the efficiency of the inhibition increases in the Cl - < Br - < I - order. The activity of JBU upon [Ag(PEt 3 ) 2 ]NO 3 addition decreases to a plateau corresponding to ca. 60% of the original activity and decreases with time at a reduced rate. Synchrotron X-ray crystallography on single crystals obtained after the incubation of SPU with the Ag(I) complexes yielded high-resolution (1.63-1.97 Å) structures. The metal-protein adducts entail a dinuclear Ag(I) cluster bound to the conserved residues αCys322, αHis323, and αMet367, with a bridging cysteine thiolate atom, a weak Ag … Ag bond, and a quasi-linear Ag(I) coordination geometry. These observations suggest a mechanism that involves the initial substitution of the phosphine ligand, followed by a structural rearrangement to yield the dinuclear Ag(I) cluster. These findings indicate that urease, in addition to the active site dinuclear Ni(II) cluster, possesses a secondary metal binding site, located on the mobile flap domain, capable of recognizing pairs of soft metal ions and controlling catalysis., (Copyright © 2021. Published by Elsevier Inc.)

Synthesis of a novel series of hydrazine clubbed 1,3-thiazoles (5a-m) has been described by reacting hydrazine-1-carbothioamides (3a-k) with α-chloro- or bromo-acetophenones (4a-d) in refluxing ethanol in good to excellent yields (65-86%). Structural confirmation was based upon spectroscopic techniques such as 1 H-NMR, 13 C-NMR, FT-IR and mass spectrometry. The biological application of these motifs has been demonstrated in terms of their strong urease inhibition activity. The results of in vitro study revealed that all the compounds are the potent inhibitors of urease. The IC 50 (ranging in between 110 and 440 nM) values were higher as compared to that of standard, i.e., thiourea (IC 50  = 490 ± 10 nM). The synthesized compounds were docked at the active sites of the Jack bean urease enzyme in order to explore the possible binding interactions of enzyme-ligand complexes; the results reinforced the in vitro biological activity results.

The low efficacy of current conventional treatments for bacterial infections increases mortality rates worldwide. To alleviate this global health problem, we propose drug-free enzyme-based nanomotors for the treatment of bacterial urinary-tract infections. We develop nanomotors consisting of mesoporous silica nanoparticles (MSNPs) that were functionalized with either urease (U-MSNPs), lysozyme (L-MSNPs), or urease and lysozyme (M-MSNPs), and use them against nonpathogenic planktonic Escherichia coli . U-MSNPs exhibited the highest bactericidal activity due to biocatalysis of urea into NaHCO 3 and NH 3 , which also propels U-MSNPs. In addition, U-MSNPs in concentrations above 200 μg/mL were capable of successfully reducing 60% of the biofilm biomass of a uropathogenic E. coli strain. This study thus provides a proof-of-concept, demonstrating that enzyme-based nanomotors are capable of fighting infectious diseases. This approach could potentially be extended to other kinds of diseases by selecting appropriate biomolecules.

A series of halo-substituted mixed ester/amide-based analogues 4a-l have been prepared as jack bean urease inhibitor, which showed good to excellent inhibition of enzyme activity. The role of halo-substituted benzoyl moieties and alkyl substituted anilines in urease inhibitory kinetics was also investigated. The alkyl-substituted anilines 1a-b reacted with chloroacetyl chloride to afford intermediates 2a-b , which were then reacted with different halo-substituted benzoic acids 3a-f to prepare the title compounds 4a-l . The chemical structures of final products 4a-l were ascertained by FTIR, 1 H NMR, 13 C NMR, and mass spectra. The compound 4b showed remarkable activity with IC 50 1.6 ± 0.2 nM, better than the standard thiourea having IC 50 472.1 ± 135.1 nM. The 2-chloro-substituted phenyl ring on one side of compound 4b and 4-isopropyl-substituted benzene on the other side play an essential role in inhibition of urease activity. Lineweaver-Burk plots (kinetics study) indicated about 4b derivative as a mixed type of inhibitor. The virtual screening performed against urease enzyme (PDBID 4H9M) showed that compounds 4b and 4e have binding energies of -7.8 and -7.9 Kcal/mol, respectively. Based upon our results, it was found that derivative 4b is a highly potent urease inhibitor, better than the standard thiourea., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2020 Muhammad Rashid et al.)

A series of novel flavonoid analogues were designed and synthesized. The aimed compounds for urease inhibitory activities were clearly superior to the control drug thiourea (more than 10 times). Among these compounds, L2 (IC 50  = 1.343 µM) and L12 (IC 50  = 1.207 µM) exhibited the most excellent urease inhibitory activity in vitro. The molecular dockings of L2, L12 and L22 into urease were performed to explore the binding modes and their structure-activity relationship. Furthermore, these aimed compounds showed good druggable properties., (Copyright © 2020 Elsevier Inc. All rights reserved.)

In the current study, a novel series of Schiff base derivatives of (E)-4-(benzylideneamino)-N-(4,6-dimethylpyrimidin-2-yl)benzenesulfonamide (3a-3f) and (E)-4-(benzylideneamino)-N-(5-methylisoxazol-3-yl)benzenesulfonamide (3g-3q) were synthesize. The structures of synthetic compounds were elucidated by various spectroscopic techniques such as FTIR, NMR and spectrometric HRMS analysis. Synthetic derivatives were evaluated for their Jack Bean urease inhibitory activity using established in-vitro assay. It is worth mentioning here that most of our derivatives of both series displayed moderate to strong inhibitory activity, ranging between IC 50  = 2.48 ± 0.78 µM and 35.63 ± 1.26 µM, as compared to standard thiourea (IC 50  = 20.03 ± 2.03 µM). Further, structure activity relationship studies suggest that the presence of halogen at ortho and para positions on the aryl ring in (E)-4-(benzylideneamino)-N-(4,6-dimethylpyrimidin-2-yl)benzenesulfonamide derivatives and hydroxy and halogen in (E)-4-(benzylideneamino)-N-(5-methylisoxazol-3-yl)benzenesulfonamide derivatives increased the urease inhibitory activity. Furthermore, molecular docking studies were carried out in order to investigate the binding mode of this class of compounds to urease. In order to evaluate drug likeness of compounds ADME evaluation was done, and the synthesized compounds were found to be non-toxic and present passive gastrointestinal absorption. The data suggests the synthesized sulphamethazine and sulphamethoxazole derivatives can serve as a novel scaffold to inhibit urease., (Copyright © 2020 Elsevier Inc. All rights reserved.)

An innovative signal-transduction tag based on cross-linked urease nanoparticles (CLENP) was designed for the development of a pH meter-based immunoassay of lipocalin-2 (LCN2). The CLENP was synthesized with a typical desolvation method using ethanol as desolvation agent, followed by functionalization with polyaspartic acid. The carboxylated CLENP were used as the signal-generation tags for the labelling of secondary antibodies via the carbodiimide coupling. Upon target LCN2 introduction, a sandwich-type immune reaction was performed between capture antibody-coated plate and the labeled secondary antibody on the CLENP. The conjugated CLENP in the microplate hydrolyzed urea into ammonia (NH 4 + ) and carbonate (CO 3 2- ), resulting in the pH change of solution, which was determined with a handheld pH meter. The pH variation was proportional to target concentration in the sample. By monitoring the pH variation of the urea solution, the level of LCN2 at a concentration as low as 5.2 pg mL -1  was evaluated. The pH meter-based electrochemical immunoassay can be utilized for mass production of miniaturized lab-on-a-chip devices with handheld pH meter, thereby opening new opportunities for protein diagnostics and biosecurity. Graphical abstract An innovative signal-transduction tag based on cross-linked urease nanoparticles was designed for high-efficiency immunoassay of lipocalin-2 with pH meter readout.

Sphenocentrum jollyanum seeds (MeOH extract and n butanol fraction) exhibited urease inhibitory activity (IC 50 40.0 ± 0.92, 28.6 ± 0.41). The Ethyl acetate (EtOAc) fraction gave significant antacid activity with an increase in the baseline pH value of 1.2 to 1.61 ± 0.00 and 1.53 ± 0.00 at 50 and 100 mg, respectively, compared to the antacid activity of sodium bicarbonate (1.53 ± 0.00, 1.47 ± 0.00). Five known ecdysteroid compounds isolated from S. jollyanum ethyl acetate and n butanol fractions are Pinnatasterone (1), Polypodine B (2), 20-hydroxyecdysone (3), 20, 26-dihydroxyecdysone, (4) and Atrotosterone A (5). The compounds' structures were determined using extensive 1D and 2D NMR experiments, and the molecular mass for each of the compounds was confirmed by FAB-MS. Compounds 1-5 were evaluated for their urease inhibitory and antacid activities. Fractions were active in comparison with the standard drug acetohydroxamic acid, and sodium bicarbonate, respectively. Compounds 2, 3 and 1 showed significant urease inhibitory activity (IC 50 7.0 ± 0.56, 13.8 ± 0.49 and 14.1 ± 0.59), respectively. The activity of compounds 4 and 5 were moderate compared to that of acetohydroxamic acid (IC 50 value 20.3 ± 0.43). Very few compounds have been isolated from this plant despite the numerous biological activities reported for it. The antacid and urease inhibitory activities of this plant and isolated compounds are described for the first time., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Inc. All rights reserved.)

The nickel-dependent urease enzyme is responsible for the hydrolysis of urea to ammonia and carbon dioxide. A number of bacteria produce urease (ureolytic bacteria) and are associated with various infectious diseases and ammonia emissions from agriculture. We report the first comprehensive comparison of the inhibition of urease activity by compounds analysed under the same conditions. Thus, 71 commercially available compounds were screened for their anti-ureolytic properties against both the ureolytic bacterium Klebsiella pneumoniae and purified jack bean urease. Of the tested compounds, 30 showed more than 25% inhibition of the ureolytic activity of Klebsiella pneumoniae or jack bean urease, and among these, carbon disulfide, N-phenylmaleimide, diethylenetriaminepentaacetic acid, sodium pyrrolidinedithiocarbamate, 1,2,4-butanetricarboxylic acid, tannic acid, and gallic acid have not previously been reported to possess anti-ureolytic properties. The diverse effects of metal ion chelators on ureolysis were investigated using a cellular nickel uptake assay. Ethylenediaminetetraacetic acid (EDTA) and dimethylglyoxime (DMG) clearly reduced the nickel import and ureolytic activity of cells, oxalic acid stimulated nickel import but reduced the ureolytic activity of cells, 1,2,4-butanetricarboxylic acid strongly stimulated nickel import and slightly increased the ureolytic activity of cells, while L-cysteine had no effect on nickel import but efficiently reduced the ureolytic activity of cells.

Thermal inactivation of oligomeric enzymes results in complex structural changes. This work deals with thermal inactivation of a native hexamer, jack bean urease. In order to find the mechanism and kinetics of thermal inactivation corresponding well with the modification of tertiary and quaternary structure of this enzyme, several types of experiments were carried out in the temperature range of 65-85 °C. Inactivation data exhibited the characteristic biphasic character. Dynamic light scattering experiments revealed a significant increase of the mean hydrodynamic radius of urease with temperature and time. A significant contribution to understanding the mechanism of inactivation was provided by native gel electrophoresis data of inactivated samples. Simultaneous fit of inactivation data verified a two-step mechanism composed of reversible unfolding/folding reaction followed by a relatively fast aggregation of the denatured urease form. A complex reaction scheme containing numerous oligomeric forms was thus described by a relatively simple model which suitably represents the main types of reactions involved in the urease activity loss., (Copyright © 2019 Elsevier B.V. All rights reserved.)

A series of new deferasirox derivatives were synthesized through the reaction of monosubstituted hydrazides with 2-(2-hydroxyphenyl)-4H-benzo[e][1,3]oxazin-4-one. For the first time, deferasirox and some of its derivatives were evaluated for their in vitro inhibitory activity against Jack bean urease. The potencies of the members of this class of compounds are higher than that of acetohydroxamic acid. Two compounds, bearing tetrazole and hydrazine derivatives (bioisoester of carboxylate group), represented the most potent urease inhibitory activity with IC 50 values of 1.268 and 3.254 μm, respectively. In silico docking studies were performed to delineate possible binding modes of the compounds with the enzyme, urease. Docking analysis suggests that the synthesized compounds were anchored well in the catalytic site and extending to the entrance of binding pocket and thus restrict the mobility of the flap by interacting with its crucial amino acid residues, CME592 and His593. The overall results of urease inhibition have shown that these target compounds can be further optimized and developed as a lead skeleton for the discovery of novel urease inhibitors., (© 2020 Wiley-VHCA AG, Zurich, Switzerland.)

Six novel complexes, [Ni(C 36 H 34 N 2 O 10 )]·2.25CH 3 OH·0.5C 4 H 10 O (1), [Co(C 36 H 34 N 2 O 10 )] (2), [Cu(C 36 H 34 N 2 O 10 )]·2CH 3 OH (3), [Ni(C 36 H 32 N 2 O 8 Cl 2 )]·2CH 3 OH (4), [Co(C 36 H 32 N 2 O 8 Cl 2 )]·4CH 3 OH (5) and [Cu(C 36 H 32 N 2 O 8 Cl 2 )]·2CH 3 OH (6) with two sexidentate N 2 O 4 -donor bis-Schiff base ligands (C 36 H 34 N 2 O 10  = 1,2-bis(2-methoxy-6-formylphenoxy)ethane-l-tyrosine; C 36 H 32 N 2 O 8 Cl 2  = 1,2-bis(2-methoxy-6-formylphenoxy)ethane-l-4-chlorophenylalanine) have been synthesized and structurally characterized. Theoretical calculation of the six complexes was carried out by density functional theory (DFT) Becke's three-parameter hybrid (B3LYP) method employing the 6-3lG basis set, indicating that the calculation results are in accordance with experimental results. Moreover, the inhibitory activities of complexes 1-6 were tested in vitro against jack bean urease. At the same time, molecular docking was investigated to determine the probable binding mode. The experimental values and docking simulation exhibited that complexes 3 and 6 showed strong inhibitory activity (IC 50  = 10.36 ± 1.13, 15.63 ± 3.04 μM) compared with the positive reference acetohydroxamic acid (IC 50  = 26.99 ± 1.43 μM). Their structure-inhibitory activity relationship was further discussed from the perspective of molecular docking and theoretical calculation., (Copyright © 2019. Published by Elsevier Inc.)

Ethnopharmacological Relevance: Zanthoxylum nitidum (Roxb.) DC. is a traditional Chinese medicine characterised by anti-inflammatory and anti-Helicobacter pylori, which is widely used to treat H. pylori-induced gastric disease in China. However, the underlying mechanism related to its anti-H. pylori activity remains unclear. Urease plays a crucial role in the colonisation and survival of H. pylori., Aim of the Study: The root aqueous extract of Z. nitidum against H. pylori urease (HPU) and jack bean urease (JBU) was investigated to illuminate the inhibitory potency, kinetics and potential mechanism., Materials and Methods: Z. nitidum components were determined by UPLC. The enzyme inhibitory effects of Z. nitidum were examined using modified spectrophotometric Berthelot (phenol-hypochlorite) method. Urease inhibition kinetics were determined by Lineweaver-Burk plots. Sulfhydryl group reagents and Ni 2+ -binding inhibitors were used in the mechanism study. Moreover, the molecular docking technique was used to investigate the binding conformations of the main compounds of Z. nitidum on Urease., Results: According to UPLC results, the major components of Z. nitidum were magnoflorine, sanguinarine, nitidine chloride, chelerythrine, skimmianine and L-Sesamin. Z. nitidum has higher enzyme inhibitory activity on HPU (IC 50  = 1.29 ± 0.10 mg/mL) than on JBU (IC 50  = 2.04 ± 0.27 mg/mL). Enzyme inhibitory kinetic analysis revealed that the type of Z. nitidum inhibition against HPU was a slow-binding and mixed-type, whereas a slow-binding and non-competitive type inhibited JBU. Further mechanism study indicated that the active site of sulfhydryl group might be the target of inhibition by Z. nitidum. The molecular docking study indicated that the above six main components of Z. nitidum exhibited stronger affinity to HPU than to JBU through interacting with the key amino acid residues located on the mobile flap or interacting with the active site Ni 2+ . Results indicated that these components are potential active ingredients directed against urease., Conclusions: Z. nitidum inactivated urease in a concentration-dependent manner through slow-binding inhibition and binding to the urease active site sulfhydryl group. Our investigation might provide experimental evidence for the traditional application of Z. nitidum in the treatment of H. pylori-associated gastric disorders., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Highly ordered superstructures composed of inorganic nanoparticles appear in natural and synthetic systems, however the mechanisms of non-equilibrium self-organization that may be involved are still poorly understood. Herein, we performed a kinetic investigation of the precipitation of calcium phosphate using a process widely found in microorganisms: the hydrolysis of urea by enzyme urease. With high initial ratio of calcium ion to phosphate, periodic precipitation was obtained accompanied by pH oscillations in a well-stirred, closed reactor. We propose that an internal pH-regulated change in the concentration of phosphate ion is the driving force for periodicity. A simple model involving the biocatalytic reaction network coupled with burst nucleation of nanoparticles above a critical supersaturation reproduced key features of the experiments. These findings may provide insight to the self-organization of nanoparticles in biomineralization and improve design strategies of biomaterials for medical applications., (© 2020 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.)

Jaburetox (JBTX) is an insecticidal and antifungal peptide derived from jack bean (Canavalia ensiformis) urease that has been considered a candidate for developing genetically modified crops. This study aimed to perform the risk assessment of the peptide JBTX following the general recommendations of the two-tiered, weight-of-evidence approach proposed by International Life Sciences Institute. The urease of C. ensiformis (JBU) and its isoform JBURE IIb (the JBTX parental protein) were assessed. The history of safe use revealed no hazard reports for the studied proteins. The available information shows that JBTX possesses selective activity against insects and fungi. JBTX and JBU primary amino acids sequences showed no relevant similarity to toxic, antinutritional or allergenic proteins. Additionally, JBTX and JBU were susceptible to in vitro digestibility, and JBU was also susceptible to heat treatment. The results did not identify potential risks of adverse effects and reactions associated to JBTX. However, further allergen (e.g. serum IgE binding test) and toxicity (e.g. rodent toxicity tests) experimentation can be done to gather additional safety information on JBTX, and to meet regulatory inquiries for commercial approval of transgenic cultivars expressing this peptide., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Background: Urease enzyme catalyzes the hydrolysis of urea into ammonia and CO2, excess ammonia causes global warming and crop reduction. Ureases are also responsible for certain human diseases such as stomach cancer, peptic ulceration, pyelonephritis, and kidney stones. New urease inhibitors are developed to get rid of such problems., Objective: This article describes the synthesis of a series of novel 1-aroyl-3-(2-oxo-2H-chromen-4- yl)thiourea derivatives (5a-j) as Jack bean urease inhibitors., Methods: Freshly prepared aryl isothiocyanates were reacted with 4-aminocoumarin in the same pot in an anhydrous medium of acetone. The structures of the title thioureas (5a-j) were ascertained by their spectroscopic data. The inhibitory effects against jack bean urease were determined., Results: It was found that compounds 5i and 5j showed excellent activity with IC50 values 0.0065 and 0.0293, µM respectively. Compound 5i bearing 4-methyl substituted phenyl ring plays a vital role in enzyme inhibitory activity. The kinetic mechanism analyzed by Lineweavere-Burk plots revealed that compound 5i inhibits the enzyme non-competitively. The Michaelis-Menten constant Km and inhibition constants Ki calculated from Lineweavere-Burk plots for compound 5i are 4.155mM and 0.00032µM, respectively. The antioxidant activity results displayed that compound 5j showed excellent radical scavenging activity. The cytotoxic effects determined against brine shrimp assay showed that all of the synthesized compounds are non-toxic to shrimp larvae. Molecular docking studies were performed against target protein (PDBID 4H9M) and it was determined that most of the synthesized compounds exhibited good binding affinity with the target protein. Molecular dynamics simulation (MDS) results revealed that compound 5i forms a stable complex with target protein showing little fluctuation., Conclusions: Based upon our investigations, it is proposed that 5i derivative may serve as a lead structure for devising more potent urease inhibitors., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

A series of new hydrazonothiazolines (3a-v) was obtained in good to excellent yields (79-96%) via cyclization of the appropriate thiosemicarbazones with phenacyl bromide. The targeted compounds were characterized by advanced spectroscopic techniques, such as FTIR, 1 HNMR, 13 CNMR and ESI-MS. The structure of compounds 3n and 3v was unambiguously confirmed by single crystal X-ray analysis. All compounds displayed enhanced inhibitory activity against urease enzyme with IC 50 values in range of 1.73 ± 1.57-27.3 ± 0.655 μM when compared to standard thiourea (IC 50  = 20.8 ± 0.75 µM). The structure-activity relationship studies demonstrated that the activity of this series is due the central thiazole ring that interacts with nickel atoms in the active site of urease enzyme. Moreover, molecular docking studies were carried out to investigate the binding mode of all active compounds and an inactive (3u) with the active site of the urease enzyme. The docking results are in complete agreement with the experimental finding., (Copyright © 2019. Published by Elsevier Inc.)

The inhibition of urease enzyme is very important as it plays a key role in the treatment of several urinary and gastrointestinal tract infections. This enzyme provides a suitable environment for Helicobacter pylori at the low pH of the stomach, a causative agent of gastric and peptic ulcer that may lead to cancer. In agriculture, the high urease content causes environmental and economic problems. In this pursuit, given the well-established importance of integrated pharmacophores in medicinal chemistry and to explore new inhibitors of urease featuring two distinct heterocyclic functionalities, we herein report a facile synthesis of carbazole-triazine hybrids (3a-j). These new propeller-shaped chemical scaffolds were evaluated for their urease inhibitory potential in order to identify suitable leads. The initial structure-activity survey work guided through in vitro bioactivity results recognized 3e and 3f as new starting point hits incorporating bulky iodo (3e) and strong electron-withdrawing nitro (3f) groups at the para-position of aryl amine component. The potent compounds (3e &3f) exhibited the highest activity with IC 50 values of 5.6 and 6.7 µM, respectively. In the molecular docking analysis, these compounds depicted excellent binding interactions with the active site residues. The key interactions observed include hydrogen bonding, π-π interactions, π-cation and nickel atom coordination to the triazine nitrogen of both inhibitors., Competing Interests: Declaration of Competing Interest The authors declare that they have no conflict of interest., (Copyright © 2019 Elsevier Inc. All rights reserved.)

The concept that catalytic enzymes can act as molecular machines transducing chemical activity into motion has conceptual and experimental support, but experimental support has involved oligomeric enzymes, often studied under conditions where the substrate concentration is higher than biologically relevant and accordingly exceeds k M , the Michaelis constant. Urease, a hexamer of subunits, has been considered to be the gold standard demonstrating enhanced diffusion. Here we show that urease and certain other oligomeric enzymes dissociate above k M into their subunits that diffuse more rapidly, thus providing a simple physical mechanism that contributes to enhanced diffusion in this regime of concentrations. Mindful that this conclusion may be controversial, our findings are supported by four independent analytical techniques: static light scattering, dynamic light scattering (DLS), size-exclusion chromatography (SEC), and fluorescence correlation spectroscopy (FCS). Data for urease are emphasized and the conclusion is validated for hexokinase, acetylcholinesterase, and aldolase. For hexokinase and aldolase no enhanced diffusion is observed except under conditions when these oligomeric enzymes dissociate. At substrate concentration regimes below k M at which acetylcholinesterase and urease do not dissociate, our finding showing up to 10% enhancement of the diffusion coefficient is consistent with various theoretical scenarios in the literature.

A series of 2,5-bis(alkyl/arylamino)-1,4-benzoquinones (1-12) were investigated in vitro for their potential to inhibit the activity of jack bean urease. Compounds 1-6, 8, 9, 11 and 12 effectively inhibited the jack bean urease activity by 90.8 % when tested at 5 μm, whereas 7 and 10 had relatively little effect. The IC 50 for most compounds was in the nanomolar range (31.4 nm and 36.0 nm for 2 and 8, respectively). The mechanism of enzyme inhibition shown by 2 and 8 is typical of mixed-type inhibitors, whose affinity for the active site is over 6- and 2-fold higher (K i =30.0 and 22.8 nm, for 2 and 8, respectively) than that of an allosteric site. Molecular docking studies revealed that both 2 and 8 establish hydrogen bonds with the amino acids residues Asp494, Met588, His593 and Ala636 in the active site of jack bean urease. These results indicate that such aminoquinones are useful leads for the development of more efficient urease inhibitors of wider utility., (© 2019 Wiley-VHCA AG, Zurich, Switzerland.)

Food fraud includes the addition of inferior components or the substitution of substances. Besides being of economic concern, this might furthermore pose a health risk for consumers. Therefore, the detection of replacements is of high importance. For the identification of species, in recent years proteomic methods gained more and more importance. In this work, an easy and efficient approach of targeted peptide analytics for revealing food fraud is presented. One of the most common workflows for protein analytics was improved by the application of urease to hydrolyze the urea in the extraction buffer; therefore, no further cleanup is required. By considering only selected compounds and the use of open-source databases for the selection of the target peptides for the adoption of the analytical methods, no time-consuming basic research is required. For the detection of the substitutes, it is not necessary to know the absolute concentration of the component. In these cases, the calculation of the proportion of a species in relation to the total content of all analyzed compounds is sufficient.

The studied enzyme-based biocatalytic system mimics NXOR Boolean logic gate, which is a logical operator that corresponds to equality in Boolean algebra. It gives the functional value true (1) if both functional arguments (input signals) have the same logical value (0,0 or 1,1), and false (0) if they are different (0,1 or 1,0). The output signal producing reaction is catalyzed by pyrroloquinoline quinone-dependent glucose dehydrogenase (PQQ-GDH), which is inhibited at acidic and basic pH values. Two other reactions catalyzed by esterase and urease produce acetic acid and ammonium hydroxide, respectively, shifting solution pH from the optimum pH for PQQ-GDH to acidic and basic values (1,0 and 0,1 input combinations, respectively), thus switching the enzyme activity off (output 0). When the input signals are not applied (0,0 combination) or both applied compensating each other (1,1 combination) the optimum pH is preserved, thus keeping PQQ-GDH running at the high rate (output 1). The biocatalytic cascade mimicking the NXOR gate was characterized optically and electrochemically. In the electrochemical experiments the PQQ-GDH enzyme communicated electronically with a conducting electrode support, thus resulting in the electrocatalytic current when signal combinations 0,0 and 1,1 were applied. The logic gate operation, when it was realized electrochemically, was also extended to the biomolecular release controlled by the gate. The release system included two electrodes, one performing the NXOR gate and another one activated for the release upon electrochemically stimulated alginate hydrogel dissolution. The studied system represents a general approach to the biocatalytic realization of the NXOR logic gate, which can be included in different catalytic cascades mimicking operation of concatenated gates in sophisticated logic circuitries., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Fumarate diester 3 was synthesized upon reacting anthranilic acid with diethylacetylenedicarboxylate. Compound 3 was reacted with different nucleophiles in mild reaction conditions. Selected reaction routes that afforded products 6, 9, 10, 11, and 12 were explained. The estimated mechanism for the reaction of 3 with ethylenediamine to afford 9 was proved by X-ray single-crystal and retro-synthetic reaction. Acetyl anthranilic acid was utilized with zinc and copper to afford the organometallic compounds 14a and 14b, respectively. Three single crystals were afforded for 3, 9 and the organocopper complex 14b. Target compounds were screened for their inhibitory potential against urease enzyme. Most compounds were more potent than thiourea as standard inhibitor, considering that oxopiperazine 9 exhibited double the activity: IC 50 = 8.16 ± 0.65 µM (thiourea IC 50 = 20.04 ± 0.33 µM). Docking studies were in agreement with the in vitro enzyme assay., (© 2019 Deutsche Pharmazeutische Gesellschaft.)

Bio-catalytic micro- and nanomotors self-propel by the enzymatic conversion of substrates into products. Despite the advances in the field, the fundamental aspects underlying enzyme-powered self-propulsion have rarely been studied. In this work, we select four enzymes (urease, acetylcholinesterase, glucose oxidase, and aldolase) to be attached on silica microcapsules and study how their turnover number and conformational dynamics affect the self-propulsion, combining both an experimental and molecular dynamics simulations approach. Urease and acetylcholinesterase, the enzymes with higher catalytic rates, are the only enzymes capable of producing active motion. Molecular dynamics simulations reveal that urease and acetylcholinesterase display the highest degree of flexibility near the active site, which could play a role on the catalytic process. We experimentally assess this hypothesis for urease micromotors through competitive inhibition (acetohydroxamic acid) and increasing enzyme rigidity (β-mercaptoethanol). We conclude that the conformational changes are a precondition of urease catalysis, which is essential to generate self-propulsion.

Graphene has strong potential for electrical biosensing owing to its two-dimensional nature and high carrier mobility which transduce the direct contact of a detection target with a graphene channel to a large conductivity change in a graphene field-effect transistor (G-FET). However, the measurable range from the graphene surface is highly restricted by Debye screening, whose characteristic length is less than 1 nm at physiological ionic strength. Here, we demonstrated electrical biosensing utilizing the enzymatic products of the target. We achieved quantitative measurements of a target based on the site-binding model and real-time measurement of the enzyme kinetics in femtoliter microdroplets. The combination of a G-FET and microfluidics, named a "lab-on-a-graphene-FET", detected the enzyme urease with high sensitivity in the zeptomole range in 100 mM sodium phosphate buffer. Also, the lab-on-a-graphene-FET detected the gastric cancer pathogen Helicobacter pylori captured at a distance greater than the Debye screening length from the G-FET.

An efficient, one-pot and four-component synthesis of a new series of 2,3-disubstituted isoindolin-1-ones is described and their Jack bean urease inhibitory activities are evaluated. Heating a mixture of 1,1-bis(methylthio)-2-nitroethene, a 1,2-diamine, a 2-formylbenzoic acid and a primary amine in EtOH for 3.5 h afforded the corresponding 2,3-disubstituted isoindolin-1-ones in good to excellent yields. All sixteen synthesized isoindolin-1-one derivatives 5a-p showed urease inhibitory activity. Among them, 5c showed the most urease inhibitory activity (IC 50  = 10.07 ± 0.28 µM) being over 2-fold more potent than thiourea (IC 50  = 22.01 ± 0.10 µM) and 10-fold than hydroxyurea (IC 50  = 100.00 ± 0.02 µM) as the standard inhibitors, respectively. Also, results from molecular docking studies were in good agreement with those obtained from in vitro tests., (Copyright © 2019. Published by Elsevier Inc.)

A new series of N-substituted thiosemicarbazones (3a-u) bearing 2-naphthyl and dihydrobenzofuranyl scaffolds were synthesized in good to excellent yields (78-95%). The synthesized compounds were characterized by advanced spectroscopic techniques, such as FTIR, 1 HNMR, 13 CNMR and ESI-MS and evaluated as urease inhibitors. The structure of compound 3m was unambiguously confirmed by single crystal X-ray analysis. All compounds showed remarkable activities against urease enzyme with IC 50 values in range of 1.4-36.1 µM. The majority of the synthesized compounds showed higher activity than the standard compound thiourea. Molecular docking was performed to study the mode of interaction of these compounds and their structure-activity relationship. These studies revealed that the compounds bind at the active site and interacts with the nickel atom present in the binding site. The molecular docking demonstrated excellent co-relations with the experimental findings., (Copyright © 2019 Elsevier Inc. All rights reserved.)

A series of novel tricyclic quinazolinone-iminosugars 1 (a-c) were synthesized from the benzyl protected sugars through three steps. Firstly, the benzyl protected sugar (aldehyde) 5 reacted with o-aminobenzamide by the iodine-induced oxidative condensation to afford the corresponding aldo-quizanolinone 6. Secondly, through the intramolecular cyclization of the unprotected OH and the amide NH in 6, the tricyclic compounds 7 and 8 were constructed by the key Mitsunobu reaction. Finally, removal of the benzyl group gave the target tricyclic quinazolinone-iminosugars 1. The protocol was effective for the preparation of the tricyclic iminosugars in satisfactory yield. Interestingly, an unusual C-2 epimerization was observed with d-mannose and d-ribose compounds under the conditions of the Mitsunobu reaction that generated the products having the trans configuration at the C-2 and C-3 positions. Unfortunately, such tricyclic quinazolinone-iminosugars showed no inhibitory effects on the tested five glycosidases., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

In an attempt to achieve a new class of phosphoramide inhibitors with high potency and resistance to the hydrolysis process against urease enzyme, we synthesized a series of bisphosphoramide derivatives (01-43) and characterized them by various spectroscopic techniques. The crystal structures of compounds 22 and 26 were investigated using X-ray crystallography. The inhibitory activities of the compounds were evaluated against the jack bean urease and were compared to monophosphoramide derivatives and other known standard inhibitors. The compounds containing aromatic amines and their substituted derivatives exhibited very high inhibitory activity in the range of IC 50  = 3.4-1.91 × 10 -10  nM compared with monophosphoramides, thiourea, and acetohydroxamic acid. It was also found that derivatives with PO functional groups have higher anti-urease activity than those with PS functional groups. Kinetics and docking studies were carried out to explore the binding mechanism that showed these compounds follow a mixed-type mechanism and, due to their extended structures, can cover the entire binding pocket of the enzyme, reducing the formation of the enzyme-substrate complex. The quantitative structure-activity relationship (QSAR) analysis also revealed that the interaction between the enzyme and inhibitor is significantly influenced by aromatic rings and PO functional groups. Collectively, the data obtained from experimental and theoretical studies indicated that these compounds can be developed as appropriate candidates for urease inhibitors in this field., (Crown Copyright © 2019. Published by Elsevier Inc. All rights reserved.)

The increasing resistance of pathogens to common antibiotics, as well as the need to control urease activity to improve the yield of soil nitrogen fertilization in agricultural applications, has stimulated the development of novel classes of molecules that target urease as an enzyme. In this context, the newly developed compounds on the basis of 1-heptanoyl-3-arylthiourea family were evaluated for Jack bean urease enzyme inhibition activity to validate their role as potent inhibitors of this enzyme. 1-Heptanoyl-3-arylthioureas were obtained in excellent yield and characterized through spectral and elemental analysis. All the compounds displayed remarkable potency against urease inhibition as compared to thiourea standard. It was found that novel compounds fulfill the criteria of drug-likeness by obeying Lipinski's rule of five. Particularly compound 4a and 4c can serve as lead molecules in 4D (drug designing discovery and development). Kinetic mechanism and molecular docking studies also carried out to delineate the mode of inhibition and binding affinity of the molecules., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Self-assembled polypseudorotaxanes (PPRXs) fabricated with α-cyclodextrin and poly(ethylene glycol) (PEG) or its thiolated derivatives were candidate functional materials for enzyme soft-immobilization, encapsulation and controlled-release. The study of their interaction with Jack bean urease (JBU) indicated that they inconspicuously influenced the activity and stability of JBU during long storage, up to 30 days. The macro-species were inaccessible to JBU's active site and the steric effect might play a significant role in the stabilization of JBU, when compared with the small-molecular sulfhydryl inhibitor thioglycolic acid. Circular dichroism and fluorescence spectra analyses revealed that thiolated PEG 400 -(SH) 2 and its assembly PPRX 400 (SH) brought in perturbations to certain α-helical or β-sheet domains of JBU, making JBU's conformation more flexible. The resulting partial unfolding of domains exposed several hydrophobic clusters and varied JBU's surface hydrophobicity. It also rendered the chromophores more hydrophilic and more bared to the polar environment, leading to the typical bathochromic-shift and quenching in intrinsic and synchronous fluorescence spectra. Moreover, the surface hydrophobicity profile of JBU was depicted by fluorescent probe monitoring and the unique "hydrophobic cave" motif was proposed by analyzing JBU's structural data from the Protein Data Bank. It should be pointed out that conformational variations mainly occurred at the surface region of JBU, while the buried active bi-nickel center was not markedly influenced by the macro-species. The results demonstrated that the PPRXs might act as a proper carrier for JBU encapsulation or soft-immobilization., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Present work aimed to synthesize some unique bi-heterocyclic benzamides as lead compounds for the in vitro inhibition of urease enzyme, followed by in silico studies. These targeted benzamides were synthesized in good yields through a multi-step protocol and their structures were confirmed by IR, 1 H NMR, 13 C NMR, EI-MS and elemental analysis. The in vitro screening results showed that most of the ligands exhibited good inhibitory potentials against the urease. Chemo-informatics analysis envisaged that all these compounds obeyed the Lipinski's rule. Molecular docking results showed that 7h exhibited good binding energy value (-8.40 kcal/mol) and was bound within the active region of urease enzyme. From the present investigation, it was inferred that some of these potent urease inhibitors might serve as novel templates in drug designing., (Copyright © 2018 Elsevier Inc. All rights reserved.)

A new series of quinazolinone derivatives containing triazole, thiadiazole, thiosemicarbazide functionalities was synthesized and then screened for their in vitro urease inhibition properties. Most of the compounds showed excellent activity with IC 50 values ranging between 1.88 ± 0.17 and 6.42 ± 0.23 µg/mL, compared to that of thiourea (IC 50  = 15.06 ± 0.68) and acetohydroxamic acid (IC 50  = 21.03 ± 0.94), as reference inhibitors. Among the synthesized molecules, compounds 5c, 5e and 5a showed the best inhibitory effect against urease enzyme with IC 50 values of 1.88 ± 0.17 µg/mL, 1.90 ± 0.10 and 1.96 ± 0.07 µg/mL, respectively. Moreover in order to give better understanding of the inhibitory activity of synthesized compounds, molecular docking studies were applied at the target sites of jack bean urease enzyme (JBU). Their binding poses and energy calculations were analyzed using induced fit docking (IFD) and prime-MMGBSA tool. Binding poses of studied compounds were determined using induced fit docking (IFD) algorithms., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Urease is an enzyme of amidohydrolase family and is responsible for the different pathological conditions in the human body including peptic ulcers, catheter encrustation, kidney stone formation, hepatic coma, encephalopathy, and many others. Therefore, the search for potent urease inhibitors has attracted major scientific attention in recent years. Urea and thiourea derivatives of tryptamine (1-25) were synthesized via reaction of tryptamine with different substituted phenyl isocyanates/isothiocyanates. The synthetic compounds were evaluated for their urease enzyme inhibitory activity and they exhibited good inhibitory potential against urease enzyme in the range of (IC 50  = 11.4 ± 0.4-24.2 ± 1.5 μM) as compared to the standard thiourea (IC 50  = 21.2 ± 1.3 μM). Out of twenty-five compounds, fourteen were found to be more active than the standard. Limited structure-activity relationship suggested that the compounds with CH 3 , and OCH 3 substituents at aryl part were the most potent derivatives. Compound 14 (IC 50  = 11.4 ± 0.4 μM) with a methyl substituent at ortho position was found to be the most active member of the series. Whereas, among halogen substituted derivatives, para substituted chloro compound 16 (IC 50  = 13.7 ± 0.9 μM) showed good urease inhibitory activity. These synthetic derivatives were found to be non-cytotoxic in cellular assay. Kinetic studies revealed that the compounds 11, 12, 14, 17, 21, 22, and 24 showed a non-competitive type of inhibition. In silico study identified the possible bindings interactions of potential inhibitors with the active site of enzyme. These newly identified inhibitors of urease enzyme can serve as leads for further research and development., (Copyright © 2018. Published by Elsevier Inc.)

In this study, on the basis of the biomineralization capability of urease, a facile, one-step, and green synthetic method has been proposed for the fabrication of gold nanoclusters (AuNCs). The prepared urease-encapsulated AuNCs (U-AuNCs) exhibited strong red fluorescence emission (λ em = 630 nm) with a quantum yield as high as 17%. Interestingly, at a low concentration, the U-AuNC solution was found to be a dual-emissive system with the blue emission of the dityrosine (diTyr) residues of urease and the red emission of the embedded AuNCs. Further experiments demonstrated that p-nitrophenol (PNP) can selectively suppress the 410 nm emission of the diTyr residues of U-AuNCs without affecting the red emission of the U-AuNCs. The fluorescence quenching mechanism between U-AuNCs and PNP was systematically studied, and the leading role of the inner filter effect (IFE) was identified. Additionally, based on the sulfatase-catalyzed hydrolysis of p-nitrophenyl sulfate (PNPS) to release PNP, a self-referenced ratiometric detection method for sulfatase, which plays a crucial role in sulfur cycling, degradation of sulfated glycosaminoglycans and glycolipids, and extracellular remodeling of sulfated glycosaminoglycans, was developed by using dual-emissive U-AuNCs as the signal readout, in which the diTyr residues served as the probe and the AuNCs functioned as the internal reference. This IFE-based ratiometric sensing strategy showed a good linear relationship over the range of 0.01-1 U/mL ( R 2 = 0.997). The detection limit for sulfatase activity was 0.01 U/mL. The developed protocol was successfully used to detect sulfatase activity in human serum samples. The simplicity, rapidity, low cost, high credibility, good reproducibility, and excellent selectivity of the detection platform serve as an inspiration for further applications of fluorescent AuNCs in chemo/biosensing.

The present study focuses on the design and synthesis of a cage-like organic skeleton containing two triazole rings jointed via imine linkage. These molecules can act as urease inhibitors. The in-vitro urease inhibition screening results showed that the combination of the two triazole skeleton in the cage-like morphology exhibited comparable urease inhibition activity to that of the reference thiourea while the metallic complexation, especially with copper, nickel, and palladium, showed excellent activity results with IC 50 values of 0.94 ± 0.13, 3.71 ± 0.61, and 7.64 ± 1.21 ( 3a ⁻ c ), and 1.20 ± 0.52, 3.93 ± 0.45, and 12.87 ± 2.11 µM ( 4a ⁻ c ). However, the rest of compounds among the targeted series exhibited a low to moderate enzyme inhibition potential. To better understand the compounds' underlying mechanisms of the inhibitory effect ( 3a and 4a ) and their most active metal complexes ( 3b and 4b ), we performed an enzymatic kinetic analysis using the Lineweaver⁻Burk plot in the presence of different concentrations of inhibitors to represent the non-competitive inhibition nature of the compounds, 3a , 4a , and 4b , while mixed type inhibition was represented by the compound, 3b . Moreover, molecular docking confirmed the binding interactive behavior of 3a within the active site of the target protein.

The analysis of exosomes, which shows an increasing potential as prognostic biomarkers for non-invasive cancer diagnosis, can reveal their biological functions and disease associations. Nevertheless, the development of a convenient and quantitative method for determination of exosomes is still challenging. Herein, a novel approach for exosome quantification using pH test paper is developed via HRP-mediated promotion of mussel-inspired surface engineering and reagent-free functionalization of urease molecules. Uerase can hydrolyse urea into ammonia and carbon dioxide, and simultaneously raise the pH value of the solution. By establishing the relationship between exosome recognition and the change of pH value of the sensing solution, we can directly employ the low-cost, widely used and commercially available pH test paper to quantitatively analyse exosomes. The pH-responsive bioassay enables sensitive detection of exosomes with a detection of limit down to 4.46 × 10 3 particles/µL and can be successfully applied for determination of exosomes in clinical specimens. The versatility and reliability of our sensing platform may open up opportunities towards paper-based diagnosis of cancer., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Non-covalent complexes of urease/polyethylene glycol (PEG)-aldehyde were synthesized using regular molar ratios of urease and PEG-aldehyde at room temperature. The physical properties of the non-covalent complexes were analyzed in order to investigate the impact of coupling ratio, temperature, pH, storage stability, and thermal stability. Urease activity was analyzed by UV-Vis spectrophotometer at 630 nm. The results showed that the strongest thermal resistance was obtained using n U /n PEG :1/1 (mg/mL) complex within all molar ratios tested. The enzymatic activity of n U /n PEG :1/1 complex doubled the activity of the free enzyme. Therefore, this complex was chosen to be used in the analyses. When coupled with PEG-aldehyde, urease exhibited improved activity between pH 4.0-9.0 and the optimum pH was found to be 7.0. The thermal inactivation results of the complex demonstrated that higher activity remained (40%) when compared with the free enzyme (10%) at 60 °C. The storage stability of the non-covalent complex was 4 weeks which was greater than the storage stability of the free enzyme. A kinetic model was suggested in order to reveal the mechanism of enzymatic conversion. Potentiometric urea biosensor was prepared using two different membranes: carboxylated poly vinyl chloride (PVC) and palmitic acid containing PVC. The potentiometric responses of both sensors were tested against pH and temperature and the best results were obtained at pH 7.0 and 20-30 °C. Also, selectivity of the suggested biosensors toward Na + , Li + Ca 2+ , and K + ions was evaluated and the reproducibility responses of the urea biosensors were measured with acceptable results.

A conductometric immunoassay protocol was designed for the sensitive detection of a liver cancer biomarker, alpha-fetoprotein (AFP), in biological fluids by using enzyme-conjugated nanometer-sized enzyme-doped silica beads. Initially, urease molecules were doped into nanosilica particles by using the reverse micelle method. Thereafter, arginase-labeled anti-AFP antibodies were covalently conjugated onto the surface of the synthesized nanoparticles. The immunoreaction was carried out in a monoclonal anti-AFP capture antibody-coated microplate with a sandwich-type assay format by using bienzyme-functionalized silica nanobeads as the recognition elements. Upon l-arginine introduction, the substrate was cleaved into urea and l-ornithine on the basis of the arginase enzymatic reaction, and the as-produced urea was then decomposed into ammonia (NH4+) and bicarbonate (HCO3-) ions by the doped urease, thus causing the variation in the local conductivity of the detection solution on an interdigitated conductometric transducer. Under optimal conditions, the developed immunosensing system exhibited good conductometric responses toward target AFP within a dynamic linear range of 0.01-100 ng mL-1 at a relatively low detection limit of 4.8 pg mL-1 based on the 3sB criterion. Importantly, good reproducibility, high specificity and acceptable method accuracy were acquired for the analysis of human serum specimens in liver cancer patients.

1,2,4-Triazole derivatives containing a piperazine nucleus (4a-d and 10) were prepared starting from 1-(2-methoxyphenyl)piperazine or ethyl 4-(4-amino-2-fluorophenyl)piperazine-1-carboxylate via several steps. The synthesis of fifteen compounds (7a-l and 13a-c), which can be considered as new analogues of azole class antifungals was performed starting from 1,2,4-triazoles (4a-d and 10) via three steps containing the condensation with 2-bromo-1-(4-chlorophenyl)ethanone, reduction of carbonyl group to alcohol and alkylation of OH group, respectively. All the reactions were examined under conventional, ultrasound and microwave irradiation conditions as green chemistry techniques, and optimum conditions were defined. The newly synthesized compounds were screened for their biological potentials including antimicrobial, antioxidant, antiurease and anti α-glucosidase activities and promising results were obtained. The enzyme inhibitory potentials of these compounds were further validated through molecular docking., (Copyright © 2018 Elsevier Inc. All rights reserved.)