Inhibition of carbonic anhydrases from the extremophilic bacteria Sulfurihydrogenibium yellostonense (SspCA) and S. azorense (SazCA) with a new series of sulfonamides incorporating aroylhydrazone-, [1,2,4]triazolo[3,4-b][1,3,4]thiadiazinyl- or 2-(cyanophenylmethylene)-1,3,4-thiadiazol-3(2H)-yl moieties

A series of new sulfonamides was prepared starting from 2-oxo-N′-(4-sulfamoylphenyl)-propanehydrazonoyl chloride, a sulfanilamide derivative, which was reacted with aroylhydrazides, amines, or thiols. A library of derivatives incorporating aroylhydrazone, [1,2,4]triazolo[3,4-b][1,3,4]thiadiazinyl- or 2-(cyanophenyl-methylene)-1,3,4-thiadiazol-3(2H)-yl moieties was thus synthesized. The new compounds were investigated as inhibitors of four α-carbonic anhydrases (CAs, EC 4.2.1.1), the human (h) isoforms hCA I and II, and the bacterial ones recently isolated from the extremophilic bacteria Sulfurihydrogenibium yellostonense (SspCA) and Sulfurihydrogenibium azorense (SazCA). Low nanomolar activity was observed against hCA II (K_Is of 0.56–17.1 nM) whereas hCA I was less inhibited by these compounds (K_Is of 86.4 nM–32.8 μM). The bacterial CAs were also effectively inhibited by these derivatives (K_Is in the range of 0.77–234 nM against SazCA, and of 6.2–89.1 against SspCA, respectively), with several low nanomolar/subnanomolar inhibitors detected against both of them. As SspCA and SazCA are among the most thermostable and catalytically active CAs, it is of interest to find modulators of their activity for potential biotechnologic applications.     

Inhibition of Aspartate Aminotransferase by Glycation In Vitro Under Various Conditions

Incubation of 50 mM d -glucose with aspartate aminotransferase (AST, EC 2.6.1.1) preparations (purified pig heart enzyme or a rat liver 20,000 × g supernatant) at 25°C had no effect on enzyme activity. 50 mM d -fructose or d -ribose gradually inhibited pig heart AST under the same conditions to zero activity after 14 days. 50 mM dl -glyceraldehyde decreased enzyme activity to zero after 6 days of incubation. The inhibition of pig heart AST by 50 mM d -fructose or d -ribose was marked even at a temperature of 4°C but it was less pronounced than at 25°C. There was no effect of 0.5 mM 2-oxoglutarate on AST activity during incubation, while the presence of 25 mM l -aspartate decreased it rapidly. 0.5 mM 2-oxoglutarate partly prevented inhibition of AST by d -ribose or d -fructose, while an analogous experiment with 25 mM aspartate resulted in a rapid decline similar to that in the absence of sugars.     

Deanol Affects Choline Metabolism in Peripheral Tissues of Mice

Abstract: The enzymatic hydrolysis of UDP-galactose in rat and calf brain was studied. The hydrolysis occurs in two steps: The first is the conversion of UDP-galactose to galactose-1-phosphate catalyzed by nucleotide pyrophosphatase (EC 3.6.1.9), and the second is the conversion of the latter to free galactose by alkaline phosphatase (EC 3.1.3.1). The overall conversion has a pH optimum of 9.0, but there is considerable activity at pH 7.4, which is the optimum for UDP-galactose:ceramide galactosyltransferase in the synthesis of cerebrosides. Preparations from cytosol from calf brain cerebellum or stem that were enriched in UDP-galactose hydrolytic activity inhibit cerebroside synthesis under conditions optimal for the synthesis. Microsome-rich and nuclear debris fractions contain the highest apparent specific activity among the subcellular fractions studied. Hydrolysis of UDP-galactose occurs in all areas of brain, brainstem having the highest activity. The apparent specific activity in jimpy mouse brain homogenate is nearly twice as high as in the control brain homogenate.     

Effects of detergents on catalytic activity of human endometase/matrilysin 2, a putative cancer biomarker

Matrix metalloproteinases (MMPs) are a family of hydrolytic enzymes that play significant roles in development, morphogenesis, inflammation, and cancer invasion. Endometase (matrilysin 2 or MMP-26) is a putative early biomarker for human carcinomas. The effects of the ionic and nonionic detergents on catalytic activity of endometase were investigated. The hydrolytic activity of endometase was detergent concentration dependent, exhibiting a bell-shaped curve with its maximum activity near the critical micelle concentration (CMC) of nonionic detergents tested. The effect of Brij-35 on human gelatinase B (MMP-9), matrilysin (MMP-7), and membrane-type 1 MMP (MT1-MMP) was further explored. Their maximum catalysis was observed near the CMC of Brij-35 (∼ 90 μM). Their IC₅₀ values were above the CMC. The inhibition mechanism of MMP-7, MMP-9, and MT1-MMP by Brij-35 was a mixed type as determined by Dixon’s plot; however, the inhibition mechanism of endometase was noncompetitive with a K_i value of 240 μM. The catalytic activities of MMPs are influenced by detergents. Monomer of detergents may activate and stabilize MMPs to enhance catalysis, but micelle of detergents may sequester enzyme and block the substrate binding site to impede catalysis. Under physiological conditions, a lipid or membrane microenvironment may regulate enzymatic activity.     

Comparison of Karanjin with other nitrification inhibitors for retardation of nitrification of urea N in soil

Summary Comparative evaluation of Kranjin and three patented nitrification inhibitors for retardation of nitrification of urea in a sandy clay loam showed that the effectiveness of the compounds tested decreased in the order: Nitrapyrin>Karanjin>A.M.>dicyandiamide.     

Synthesis,molecular docking,acetylcholinesterase and butyrylcholinesterase inhibitory potential of thiazole analogs as new inhibitors for Alzheimer disease

A series of thirty (30) thiazole analogs were prepared, characterized by ¹H NMR, ¹³C NMR and EI-MS and evaluated for Acetylcholinesterase and butyrylcholinesterase inhibitory potential. All analogs exhibited varied butyrylcholinesterase inhibitory activity with IC₅₀ value ranging between 1.59 ± 0.01 and 389.25 ± 1.75 μM when compared with the standard eserine (IC₅₀, 0.85 ± 0.0001 μM). Analogs 15, 7, 12, 9, 14, 1, 30 with IC₅₀ values 1.59 ± 0.01, 1.77 ± 0.01, 6.21 ± 0.01, 7.56 ± 0.01, 8.46 ± 0.01, 14.81 ± 0.32 and 16.54 ± 0.21 μM respectively showed excellent inhibitory potential. Seven analogs 15, 20, 19, 24, 28, 30 and 25 exhibited good acetylcholinesterase inhibitory potential with IC50 values 21.3 ± 0.50, 35.3 ± 0.64, 36.6 ± 0.70, 44.81 ± 0.81, 46.36 ± 0.84, 48.2 ± 0.06 and 48.72 ± 0.91 μM respectively. All other analogs also exhibited well to moderate enzyme inhibition. The binding mode of these compounds was confirmed through molecular docking.     

Design,Synthesis and In Vitro Evaluation of Novel Benzo[b]thiophene Derivatives as Serotonin N-acetyltransferase (AANAT) Inhibitors

Serotonin N-acetyltransferase (arylalkylamine N-acetyltransferase, AANAT) is the penultimate enzyme in melatonin (5-methoxy-N-acetyltryptamine) biosynthesis. It is the key-enzyme responsible of the nocturnal rhythm of melatonin production in the pineal gland. Specific AANAT inhibitors could be useful for treatment of different physiopathological disorders encountered in diseases such as seasonal affective disorders or obesity. On the basis of previous works and 3D-QSAR studies carried out in our laboratory, we have synthesized and evaluated four novel benzo[b]thiophene derivatives designed as AANAT inhibitors. Compound 13 exhibited high inhibitory activity (IC₅₀=1.4?μM) and low affinities for both MT1 (1100?nM) and MT2 (1400?nM) receptors.     

A hydroxymethylglutaryl-CoA reductase inhibitor synthesized by yeasts

Abstract Screening of different yeast species showed that they are able to synthesize hydroxymethylglutaryl-CoA (HMGCoA) reductase inhibitors. Crude methanol extracts and the purified inhibitors from Pichia labacensis and Candida cariosilignicola were tested for their biological activity on the solubilized microsomal HMGCoA reductase from Chinese hamster ovary cells. Identification of the inhibitors was studied by thin layer chromatography, high pressure liquid chromatography and mass spectroscopy.     

Specificity of inhibition of calcium- and calmodulin-dependent protein kinase by alloxan

Studies were undertaken to determine whether the effect of alloxan to inactivate a membrane-bound calcium- and calmodulin-dependent protein kinase was specific for the pancreatic islets and whether inactivation of the kinase occurred also after injection of a diabetogenic dose of alloxan into rats. The effect of alloxan was also examined on similar particulate calcium- and calmodulin-dependent kinases present in two other secretory tissues, mammary acini and forebrain. Exposure of alloxan to cell-free preparations of all secretory tissues examined inhibited the calcium- and calmodulin-dependent kinase activities, suggesting that the specificity of alloxan action was not due to the presence in islets of a kinase uniquely sensitive to alloxan. To determine whether the selective effect of alloxan action was mediated at the cellular level, experiments were performed with alloxan presented to intact cells. Whereas alloxan exposure to viable cell preparations of islets and brain decreased the subsequently measured calcium- and calmodulin-dependent protein kinase activity, the activity measured in mammary acini exposed to these alloxan concentrations was unaffected. Injection (i.v.) of a diabetogenic dose of alloxan (50 mg/kg) produced an immediate (10 min) and selective inactivation of the calcium- and calmodulin-dependent protein kinase in pancreatic islests but had no effect on the similar kinases measured in brain and mammary acini. These results indicate that the unique sensitivity of islets to alloxan may result from the ability of alloxan to rapidly gain intracellular access and then inactivate this kinase activity. The selective effect of alloxan injection on this islet protein kinase is consistent with the hypothesis that inactivation of the kinase by alloxan is related to its diabetogenic effect in vivo.