Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.2.1.21 (beta-glucosidase)
3,280 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Orange seedlings were cultured in aqueous solutions of 3-tert-butyl-5-chloro-6-methyluracil (terbacil and terbacil-2-14C). Radioactivity was distributed throughout the plant with the largest amount in the roots and the smallest amount in the leaves. Terbacil was metabolized to form 3-tert-butyl-5-chloro-6-hydroxymethyl uracil, which was conjugated to form a beta-glucoside as the conjugate was hydrolyzed by beta-glucosidase. Identification of the metabolite was made by infrared and mass spectrometry after isolation and purification by column and thin layer chromatography. An additional unidentified water-soluble material was accumulated in the plant. 5-chloro-uracil was not detected as a metabolite of terbacil.
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PMID:Metabolism of terbacil in orange seedlings. 119 Aug 39

Using molecular genetic techniques, a fusion protein has been produced which contains the cellulose-binding domain (CBD) of an exoglucanase (Cex) from Cellulomonas fimi fused to a beta-glucosidase (Abg) from Agrobacterium sp. The CBD functions as an affinity tag for the simultaneous purification and immobilization of the enzyme on cellulose. Binding to cellulose was stable for prolonged periods at temperatures from 4 degrees C to at least 50 degrees C, at ionic strengths from 10 mM to greater than 1 M, and at pH values below 8. The fusion protein can be desorbed from cellulose with distilled water or at pH greater than 8. Immobilized enzyme columns of the fusion protein bound to cotton fibers exhibited stable beta-glucosidase activity for at least 10 days of continuous operation at temperatures up to 37 degrees C. At higher temperatures, the bound enzyme lost activity. The thermal stability of the fusion protein was greatly improved by immobilization. Immobilization did not alter the pH stability. Except for its ability to bind to cellulose, the properties of the fusion protein were virtually the same as those of the native enzyme.
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PMID:Enzyme immobilization using a cellulose-binding domain: properties of a beta-glucosidase fusion protein. 136 28

The stability and activity of three hydrolytic enzymes, acid phosphatase (EC 3.1.3.2), beta-fructofuranosidase (EC 3.2.1.26), and beta-glucosidase (EC 3.2.1.4), were studied at 30 degrees C in two-phase systems. They were prepared with equal quantities of buffered water and a water-immiscible organic solvent. Low-molecular-weight acetates and paraffins were tested in this investigation. The kinetic constant of storage inactivation was correlated with the logarithm of solvent polarity. Enzyme stability in the presence of organic phases, whose log P value was included in 1.2-2.2, was greater than the one measured in pure buffered aqueous media. On the other hand, a dramatic enzyme denaturation took place making use of solvents at higher log P-value. Experiments carried out during the 24-h operation clarified that the reaction yield does not depend solely on solvent polarity. Acid phosphatase and beta-glucosidase, which are less resistant than beta-fructofuranosidase to temperature and shear in buffered solutions, showed especially significant enhancement of catalytic activity when hydrolysis was performed with the addition of acetates (50% v/v).
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PMID:Hydrolytic reactions in two-phase systems. Effect of water-immiscible organic solvents on stability and activity of acid phosphatase, beta-glucosidase, and beta-fructofuranosidase. 136 38

We investigated the effect of maternal alcohol consumption on cell number, gangliosides and ganglioside catabolizing enzymes in the central nervous system (CNS) of the offspring. Virgin female rats of the Charles Foster strain were given 15% (v/v) ethanol in drinking water one month prior to conception and during gestation and lactation. At 21 days postnatal age, the offspring were sacrificed and the brains were separated into cerebrum, cerebellum and brain stem to investigate possible regional variations. Compared to controls, wet weight of cerebrum, cerebellum and brain stem, and of spinal cord was decreased in the pups exposed to alcohol. DNA and protein contents were also found to be lowered in all the CNS regions of the pups exposed to alcohol. Conversely, maternal alcohol consumption was found to increase the concentration and the content of total ganglioside N-acetyl-neuraminic (NANA) in CNS of the pups. In addition, alcohol treatment was found to induce alterations in the proportions of individual ganglioside fractions. Interestingly, these alterations are somewhat different than those observed in the neonatal brain and spinal cord of the pups subjected to prenatal alcohol exposure. The alterations in the proportions of ganglioside fractions were shown to be region-specific. Maternal alcohol consumption resulted in decreased activities of sialidase, beta-galactosidase, beta-glucosidase and beta-hexosaminidase. The results suggest that the alcohol-associated increases in ganglioside concentration may be at least partly due to the decreased activities of ganglioside catabolizing enzymes.
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PMID:Effect of prenatal and postnatal exposure to ethanol on rat central nervous system gangliosides and glycosidases. 140 63

Microbioassays using bacteria or enzymes are increasingly applied to measure chemical toxicity in the environment. Attractive features of these assays may include low cost, rapid response to toxicants, high sample throughput, modest laboratory equipment and space requirements, low sample volume, portability, and reproducible responses. Enzymatic tests rely on measurement of either enzyme activity or enzyme biosynthesis. Dehydrogenases are the enzymes most used in toxicity testing. Assay of dehydrogenase activity is conveniently carried out using oxidoreduction dyes such as tetrazolium salts. Other enzyme activity tests utilize ATPases, esterases, phosphatases, urease, luciferase, beta-galactosidase, protease, amylase, or beta-glucosidase. Recently, the inhibition of enzyme (beta-galactosidase, tryptophanase, alpha-glucosidase) biosynthesis has been explored as a basis for toxicity testing. Enzyme biosynthesis was found to be generally more sensitive to organic chemicals than enzyme activity. Bacterial toxicity tests are based on bioluminescence, motility, growth, viability, ATP, oxygen uptake, nitrification, or heat production. An important aspect of bacterial tests is the permeability of cells to environmental toxicants, particularly organic chemicals of hydrophobic nature. Physical, chemical, and genetic alterations of the outer membrane of E. coli have been found to affect test sensitivity to organic toxicants. Several microbioassays are now commercially available. The names of the assays and their basis are: Microtox (bioluminescence), Polytox (respiration), ECHA Biocide Monitor (dehydrogenase activity), Toxi-Chromotest (enzyme biosynthesis), and MetPAD (enzyme activity). An important feature common to these tests is the provision of standardized cultures of bacteria in freeze-dried form. Two of the more recent applications of microbioassays are in sediment toxicity testing and toxicity reduction evaluation. Sediment pore water may be assayed directly or solvents may be used to extract the toxicants. Some of the solvents used for extraction of organic chemicals are themselves toxic to bacteria (e.g., dichloromethane), requiring exchange with a less toxic solvent (e.g., ethanol, methanol, DMSO). A modification of the Microtox test allows direct assay of solid-phase samples such as sediments. The toxicity reduction evaluation (TRE) must be carried out at wastewater treatment plants whose effluents fail toxicity standards. The TREs require numerous and repeated toxicity assays, thus favoring application of microbioassays. Presently, no single microbioassay can detect all categories of environmental toxicants with equal sensitivity. Therefore, a battery of tests approach is recommended. The differential sensitivity of alternative tests may, in fact, be exploited. Further research is needed to construct strains of genetically engineered microorganisms or isolate microorganisms or enzymes that respond to specific classes of toxicants. These can be combined into batteries appropriate for different environments or test objectives.
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PMID:Bacterial and enzymatic bioassays for toxicity testing in the environment. 150 75

Second-crop, mixed grass-legume forage was ensiled in four bunker silos either untreated or after application at the forage harvester of an enzyme mixture containing cellulase, xylanase, cellobiase, and glucose oxidase, a commercial inoculant, or both additives combined. Sixteen multiparous midlactation Holstein cows in a 4 x 4 Latin square design received each silage in a 50:50 forage: concentrate diet to determine effects of silage additives on milk production and composition. Enzyme treatment reduced silage pH, concentrations of xylose and total sugars, and concentration and proportion of cell-wall arabinose. Titratable acidity, buffering capacity, concentration of residual water-soluble carbohydrate, and digestibility of DM in vitro were increased, and levels of silage structural carbohydrates were reduced. Inoculation, both alone and in the combined treatment, reduced silage pH compared with control, but inoculation alone was more effective than the combination. Enzyme treatment increased DMI and production of milk, FCM, SCM, milk protein, and milk SNF. The two silage additives were antagonistic when combined and did not improve silage fermentation, nutritional value, or animal performance, and enzyme degradation of forage structural carbohydrates was reduced. Inoculation also reduced silage aerobic stability. Combination of enzyme systems with inoculants requires careful evaluation to avoid antagonistic interactions.
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PMID:Effects of an enzyme mixture, an inoculant, and their interaction on silage fermentation and dairy production. 156 68

High-pressure liquid chromatography and microcalorimetry have been used to study the thermodynamics of the hydrolysis reactions of a series of disaccharides. The enzymes used to bring about the hydrolyses were: beta-galactosidase for lactulose and 3-o-beta-D-galactopyranosyl-D-arabinose; beta-glucosidase for alpha-D-melibiose; beta-amylase for D-trehalose; isomaltase for palatinose; and alpha-glucosidase for D-turanose. The buffer used was sodium acetate (0.02-0.10 M and pH 4.44-5.65). For the following processes at 298.15 K: lactulose(aq) + H2O(liq) = D-galactose(aq) + D-fructose(aq), K0 = 128 +/- 10 and delta H0 = 2.21 +/- 0.10 kJ mol-1; alpha-D-melibiose(aq) + H2O(liq) = D-galactose(aq) + D-glucose(aq), K0 = 123 +/- 42 and delta H0 = -0.88 +/- 0.50 kJ mol-1; palatinose(aq) + H2O(liq) = D-glucose(aq) + D-fructose(aq), delta H0 = -4.44 +/- 1.1 kJ mol-1; D-trehalose(aq) + H2O(liq) = 2 D-glucose(aq), K0 = 119 +/- 10 and delta H0 = 4.73 +/- 0.41 kJ mol-1; D-turanose(aq) + H2O(liq) = D-glucose(aq) + D-fructose(aq), delta H0 = -2.68 +/- 0.75 kJ mol-1; and 3-o-beta-D-galactopyranosyl-D-arabinose(aq) + H2O(liq) = D-galactose(aq) + D- arabinose(aq),0H0 = 107 +/- 10 and delta H0 = 2.97 +/- 0.10 kJ mol-1.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Thermodynamics of hydrolysis of disaccharides. Lactulose, alpha-D-melibiose, palatinose, D-trehalose, D-turanose and 3-o-beta-D-galactopyranosyl-D-arabinose. 187 72

The beta-glucosidase from Schizophyllum commune was purified to homogeneity by a modified procedure that employed Con A-Sepharose. The participation of carboxyl groups in the mechanism of action of the enzyme was delineated through kinetic and chemical modification studies. The rates of beta-glucosidase-catalyzed hydrolysis of p-nitrophenyl-beta-D-glucoside were determined at 27 degrees C and 70 mM ionic strength over the pH range 3.0-8.0. The pH profile gave apparent pK values of 3.3 and 6.9 for the enzyme-substrate complex and 3.3 and 6.6 for the free enzyme. The enzyme is inactivated by Woodward's K reagent and various water-soluble carbodiimides; chemical reagents selective for carboxyl groups. Of these reagents, 1-ethyl-3-(4-azonia-4,4-dimethylpentyl)carbodiimide iodide in the absence of added nucleophile was the most effective and a kinetic analysis of the modification indicated that one molecule of carbodiimide is required to bind to the beta-glucosidase for inactivation. Employing a tritiated derivative of the carbodiimide, 44 carboxyl groups in the enzyme were found to be labelled while the competitive inhibitor deoxynojirimycin protected three residues from modification. Treatment of the enzyme with tetranitromethane resulted in the modification of five tyrosine residues with approx. 28% diminution of enzymic activity. Titration of denatured enzyme with dithiobis(2-nitro-benzoic acid) indicated the absence of free thiol groups. Reaction of the enzyme with diethyl pyrocarbonate resulted in the modification of four histidine residues with the retention of 78% of the original enzymatic activity. The divalent transition metals Cu2+ and Hg2+ were found to be potent inhibitors of the enzyme, binding in an apparent irreversible manner.
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PMID:Chemical modification of a beta-glucosidase from Schizophyllum commune: evidence for essential carboxyl groups. 211 26

Human lysosomal beta-glucosidase (D-glucosyl-acylsphingosine glucohydrolase, EC 3.2.1.45) is a membrane-associated enzyme that cleaves the beta-glucosidic linkage of glucosylceramide (glucocerebroside), its natural substrate, as well as synthetic beta-glucosides. Experiments with cultured cells suggest that in vivo this glycoprotein requires interaction with negatively charged lipids and a small acidic protein, SAP-2, for optimal glucosylceramide hydrolytic rates. In vitro, detergents (Triton X-100 or bile acids) or negatively charged ganglioside or phospholipids and one of several "activator proteins" increase hydrolytic rate of lipid and water-soluble substrates. Using such in vitro assay systems and active site-directed covalent inhibitors, kinetic and structural properties of the active site have been elucidated. The defective activity of this enzyme leads to the variants of Gaucher disease, the most prevalent lysosomal storage disease. The nonneuronopathic (type 1) and neuronopathic (types 2 and 3) variants of this inherited (autosomal recessive) disease but panethnic, but type 1 is most prevalent in the Ashkenazi Jewish population. Several missense mutations, identified in the structural gene for lysosomal beta-glucosidase from Gaucher disease patients, are presumably casual to the specifically altered posttranslational oligosaccharide processing or stability of the enzyme as well as the altered in vitro kinetic properties of the residual enzyme from patient tissues.
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PMID:Acid beta-glucosidase: enzymology and molecular biology of Gaucher disease. 212 41

This investigation studied the effects of a shift from a mixed diet to a lactovegetarian diet on some cancer-associated bacterial enzymes in human feces (beta-glucuronidase, beta-glucosidase, and sulphatase). Three months after the shift to the lactovegetarian diet, there was a significant decrease in beta-glucuronidase, beta-glucosidase, and sulphatase activities per gram feces wet weight (p less than 0.05, less than 0.05, and less than 0.001, respectively). In contrast, glucuronide and glucoside hydrolysis remained unchanged per gram dry weight, although sulphatase activity was still significantly lowered when expressed this way (p less than 0.01). However, the fecal excretion increased significantly (p less than 0.05). Part of the explanation for the decreased enzyme activities is obviously a dilution effect, because much of the increased fecal weight after the shift in diet was associated with a higher water content. The higher water content was probably due to a higher fiber intake (p less than 0.001). Thus, the results in this paper indicate that a change from a mixed diet to a lactovegetarian diet leads to a decrease in certain enzyme activities proposed to be risk factors for colon cancer.
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PMID:Shift from a mixed diet to a lactovegetarian diet: influence on some cancer-associated intestinal bacterial enzyme activities. 212 19


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