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)

Micellar solutions of surfactant in organic solvents with rubber additions are proposed for determination of active enzyme concentration. A kinetic theory of enzymatic reactions in reversed micellar systems is developed, suggesting the intermicellar transport of the substrate to be the limiting step in viscous medium. Under these conditions, it is shown that fraction of the product formed after quick transformation of the substrate located in the enzyme-containing micelles depends upon active enzyme concentration and aggregation number of surfactant molecules. The proposed approach is used for the active-site titration of trypsin and cellobiase and for the determination of the aggregation number of Aerosol OT (AOT) molecules in the ternary system AOT/water/cyclohexane.
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PMID:[A new approach to titrating active enzyme centers upon the use of surface-active micellar substances in organic solvents]. 247 56

The thermodynamics of the enzymatic hydrolysis of cellobiose, gentiobiose, isomaltose, and maltose have been studied using both high pressure liquid chromatography and microcalorimetry. The hydrolysis reactions were carried out in aqueous sodium acetate buffer at a pH of 5.65 and over the temperature range of 286 to 316 K using the enzymes beta-glucosidase, isomaltase, and maltase. The thermodynamic parameters obtained for the hydrolysis reactions, disaccharide(aq) + H2O(liq) = 2 glucose(aq), at 298.15 K are: K greater than or equal to 155, delta G0 less than or equal to -12.5 kJ mol-1, and delta H0 = -2.43 +/- 0.31 kJ mol-1 for cellobiose; K = 17.9 +/- 0.7, delta G0 = -7.15 +/- 0.10 kJ mol-1 and delta H0 = 2.26 +/- 0.48 kJ mol-1 for gentiobiose; K = 17.25 +/- 0.7, delta G0 = -7.06 +/- 0.10 kJ mol-1, and delta H0 = 5.86 +/- 0.54 kJ mol-1 for isomaltose; and K greater than or equal to 513, delta G0 less than or equal to -15.5 kJ mol-1, and delta H0 = -4.02 +/- 0.15 kJ mol-1 for maltose. The standard state is the hypothetical ideal solution of unit molality. Due to enzymatic inhibition by glucose, it was not possible to obtain reliable values for the equilibrium constants for the hydrolysis of either cellobiose or maltose. The entropy changes for the hydrolysis reactions are in the range 32 to 43 J mol-1 K-1; the heat capacity changes are approximately equal to zero J mol-1 K-1. Additional pathways for calculating thermodynamic parameters for these hydrolysis reactions are discussed.
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PMID:Thermodynamics of hydrolysis of disaccharides. Cellobiose, gentiobiose, isomaltose, and maltose. 249 94

A new approach for the study of an enzyme's relationship with its own reaction medium has been developed. One technique of micellar enzymology is the use of pseudohomogeneous systems composed of surfactant/water/organic solvent. In such systems, the physicochemical properties and textures of the medium depend on the relative ratios of the different components. Enzymes are catalytically active in such systems and up to the present have been studied in different microenvironments, such as micelles, microemulsions and lyotropic liquid crystals. Our purpose was to develop a system in which the enzyme could, by its activity, modify one of the components in such a way that the relative ratios among them changed sufficiently to produce a transition from one phase domain to another. The three components, water (or glucose in water), octanol and octyl-beta-D-glucoside, form a classical ternary water/oil/surfactant system. The relevant phase diagram shows different macroheterogeneous phases and microstructured domains. The enzyme beta-D-glucosidase hydrolyses octyl-beta-D-glucoside to form glucose and octanol. The enzyme was found to change the relative ratios of water (or glucose in water), octanol and octyl-beta-D-glucoside in such a manner that the physicochemical structure of the medium was modified. At the beginning of the reaction beta-D-glucosidase was present in a micellar solution of octyl-beta-D-glucoside in water. As the enzymatic reaction proceeded, the medium became biphasic. One of the two phases was the micellar solution of octyl beta-D-glucoside in water, while the other phase was either a microemulsion or a liquid crystalline phase. In addition the enzyme, through its catalytic activity, was able to modify the physiocochemical properties of the reaction medium.
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PMID:Dynamic interactions between enzyme activity and the microstructured environment. 250 77

A hot-water extract from the seed of Plantago asiatica showed a potent inhibitory activity against jack bean alpha-mannosidase, and a flavanone glucoside, plantagoside, was isolated as the inhibitor. Plantagoside was a specific inhibitor for jack bean alpha-mannosidase (IC50 at 5 microM) and appeared to be a non-competitive inhibitor of the enzyme. Whereas, negligible or weak inhibitory activities were observed for beta-mannosidase, beta-glucosidase, and sialidase tested. Plantagoside also inhibited alpha-mannosidase activities in mouse liver lysosomal and microsomal fractions, and the enzyme inhibitory activity in microsomal fraction was enhanced in the presence of glucosidase inhibitor, castanospermine. Plantagoside suppressed antibody response to sheep red blood cells and concanavalin A induced lymphocyte proliferation which was measured by [3H]thymidine incorporation.
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PMID:Plantagoside, a novel alpha-mannosidase inhibitor isolated from the seeds of Plantago asiatica, suppresses immune response. 261 Jun 94

The possible occurrence of circadian and circannual rhythms in the plasma concentrations of the following enzymes of lysosomal origin was assessed: beta-D-N-acetylglucosaminidase (EC 3.2.1.30) beta-D-glucuronidase (EC 3.2.1.31), beta-D-glucosidase (EC 3.2.1.21), beta-D-galactosidase (EC 3.2.1.22), alpha-D-galactosidase (EC 3.2.1.23), alpha-L-fucosidase (EC 3.2.1) and alpha-D-mannosidase (EC 3.2.1.24). The circadian rhythm was studied in 16 women (aged: 17-24 years) and 13 men (age: 23 years) volunteers; the circannual rhythm, in 10 women and 8 men (age: 20-25 years). The circadian rhythm was detected in all the tested enzymes of women, and only in alpha-D-galactosidase, beta-D-glucosidase, alpha-D-mannosidase and beta-D-acetylglucosaminidase of men. A statistically significant difference between genders in the circadian rhythm was exhibited by beta-D-galactosidase (MESOR; amplitude) beta-D-glucosidase (MESOR; amplitude; acrophase) beta-D-N-acetylglucosaminidase, beta-D-glucuronidase and alpha-D-galactosidase (MESOR) and alpha-L-fucosidase (amplitude, acrophase). A circannual rhythm was detected in all the tested enzymes with the exception of beta-D-glucuronidase and beta-D-N-acetylglucosaminidase; no statistically significant difference between genders was detected. The group rhythms of some of the enzymes (alpha-D-galactosidase, beta-D-glucosidase, beta-D-galactosidase) showed similar values of both circadian and circannual acrophases, suggesting that they may subjected as a group to the same chronobiological coordination, possibly mediated by hormones. The chronobiological rhythms of lysosomal enzymes were different from those of lactate dehydrogenase and alpha 1-antitrypsin, indicating that these rhythms are not merely reflecting fluctuations of the water content of plasma. No in-phase relationship was observed between the circadian and circannual rhythms of plasma cortisol and those of the tested lysosomal enzymes, excluding a direct chronobiological and possibly functional relationship between this hormone and lysosomal enzymes.
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PMID:Chronobiological study of several enzymes of lysosomal origin in human plasma. 278 34

The circadian and circannual group rhythms in the plasma concentrations of the following lysosomal enzymes were studied in women and men: beta-D-N-acetylglucosaminidase, beta-D-glucuronidase, beta-D-glucosidase, beta-D-galactosidase, alpha-D-galactosidase, alpha-L-fucosidase and alpha-D-mannosidase. The circadian rhythm was detected in all the tested enzymes of women, and only in alpha-D-galactosidase, beta-D-glucosidase, alpha-D-mannosidase and beta-D-N-acetylglucosaminidase of men. A statistically significant difference between genders in the circadian rhythm was exhibited by beta-D-galactosidase, beta-D-glucosidase, beta-D-N-acetylglucosaminidase, beta-D-glucuronidase, alpha-D-galactosidase and alpha-L-fucosidase. A circannual rhythm was detected in all the tested enzymes, with the exception of beta-D-glucuronidase and beta-D-N-acetylglucosaminidase, without any statistically significant difference between genders. The group rhythms of some of the enzymes (alpha-D-galactosidase, beta-D-glucosidase, beta-D-galactosidase) showed similar values of both circadian and circannual acrophases, suggesting that they may be subjected as a group to the same chronobiological coordination. The chronobiological rhythms of lysosomal enzymes were different from those of lactate dehydrogenase and alpha 1-antitrypsin, indicating that these rhythms are not merely reflecting fluctuations of the water content of plasma. No in-phase relationship was observed between the circadian and circannual rhythms of plasma cortisol and those of the tested lysosomal enzymes, excluding a direct chronobiological relationship between this hormone and lysosomal enzymes.
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PMID:Circadian and circannual rhythms of several enzymes of lysosomal origin in human plasma. 313 30

Because kidney microangiopathy with capillary basement membrane thickening has been reported in spontaneous hypertension, we have studied the activities of three lysosomal glycosidases able to degrade the carbohydrate moieties of basement membrane constituents in the kidney cortex of 12-week-old spontaneously hypertensive rats (SHR) and age-matched normotensive Wistar Kyoto rats (WKY). These activities were also determined in SHR and WKY treated from 6 to 12 weeks of age with hydralazine (mean dose, 18 mg/kg per day in drinking water). Sialidase specific activity on sialyl-alpha 2-3-[3H]lactitol was markedly decreased in the kidney of untreated SHR, 40% activity remaining relative to that found in untreated age-matched WKY (p less than 0.001). beta-Galactosidase specific activity on p-nitrophenyl-beta-D-galactoside was also decreased, 86% activity remaining relative to that found in untreated WKY (p less than 0.001). Glucosyl-galactosyl-hydroxylysyl glucohydrolase specific activity on glucosyl-galactosyl-hydroxylysine was equally diminished, 74% activity remaining relative to that found in untreated age-matched WKY (p less than 0.001). In contrast, the activities of two control glycosidases inactive on the carbohydrate moieties of basement membrane constituents, alpha-glucosidase assayed with p-nitrophenyl-alpha-D-glucoside as substrate and beta-glucosidase assayed with p-nitrophenyl-beta-D-glucoside as substrate, were significantly increased. All the alterations in enzyme activities observed in the kidney of SHR were also present in the long-term treated normotensive SHR. No effect of the hydralazine treatment on the three enzyme activities investigated could be demonstrated in the WKY. Thus the alterations observed in the kidneys of SHR appear to be independent of blood pressure level.
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PMID:Alteration in sialidase and other glycosidase activities in the kidney of spontaneously hypertensive rats: persistence after preventive treatment with hydralazine. 321 99

Twenty four hour urine samples of male control and streptozotocin-diabetic Wistar rats were analysed for a series of commonly known kidney-specific enzymes, for electrolytes, creatinine, glucose, total protein and urine volume. The examination was done during two periods of 5 days between the 25th and 30th and the 32nd and 36th day after streptozotocin application. In the first period the animals had free access to food and water, whereas in the second period on days 32, 34 and 36 food was withdrawn. In the first observation period the diabetic rats showed increased excretion rates of 15 measured urinary parameters, while alanine aminopeptidase (EC 3.4.1.2) and gamma-glutamyltransferase (EC 2.3.2.2) activities were lowered and inorganic phosphate was unchanged. The removal of food resulted in decreased excretion values for alanine aminopeptidase, gamma-glutamyltransferase and total protein as compared with fasted nondiabetic animals. The activities of N-acetyl-beta-D-glucosaminidase (EC 3.2.1.30), acid phosphatase (EC 3.1.3.2), lactate dehydrogenase (EC 1.1.1.27), pyruvate kinase (EC 2.7.1.40), C1-fructose 1.6-diphosphatase (EC 3.1.3.11) and the excretion values for sodium, calcium, magnesium, chloride and glucose were higher than in fasted nondiabetic rats. beta-Glucosidase (EC 3.2.1.21), potassium, inorganic phosphate, creatinine, and urine volume showed no differences between fasted diabetic and fasted control animals. The enzymes in the renal cortex at the end of the experiment showed only decreased activity of alanine aminopeptidase in diabetic rats. Lactate dehydrogenase, pyruvate kinase, beta-glucosidase, C1-fructose 1.6-diphosphatase and glucose 6-phosphatase (EC 3.1.3.9) were increased and gamma-glutamyltransferase, N-acetyl-beta-D-glucosaminidase, acid phosphatase and glucose 6-phosphate dehydrogenase (EC 1.1.1.49) showed no change.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Enzymuria in streptozotocin-diabetic rats. 353 86

The behaviour of highly purified glucosylceramide beta-glucosidase (glucosylceramidase, EC 3.2.1.45) from human placenta [Furbish, F. S., Blair, H. E., Shiloach, J., Pentchev, P. G. & Brady, R. B. (1977) Proc. Natl Acad. Sci. USA 74, 3560-3563] was investigated in the absence of detergents with structurally modified glucosylceramides inserted into unilamellar liposomes. The reaction between the water-soluble enzyme and the liposomal substrates was significantly dependent on the structure of the lipophilic aglycon moiety of glycolipids: glucosyl-N-acetyl-sphingosines (D-erythro and L-threo) were better substrates than the corresponding glucosylceramides. The L-threo derivatives were poorer substrates with higher apparent Km values than the corresponding D-erythro derivatives. For glucosyl-3-keto-ceramide and glucosyl-dihydro-ceramide (D-erythro), higher Km values were found than for glucosylceramide. Sphingosine, glucosylsphingosine and glucosyl-N-acetyl-sphingosine were the most effective inhibitors of the hydrolysis of glucosylceramide. D-erythro-Ceramide and D-galactosyl-N-acetyl-D-erythro-sphingosine inhibited the hydrolysis of amphiphilic glucosylceramide but not that of water-soluble 4-methyl-umbelliferyl-beta-glucoside, suggesting a hydrophobic binding site of the enzyme for the aglycon moiety of its membrane-bound substrate. Dilution experiments suggested that at least a fraction of the enzyme associates with the liposomes and degrades the lipid substrate even in the absence of activator proteins. Acidic phospholipids incorporated into liposomes caused a powerful stimulation (30-40-fold) of the glucosylceramide beta-glucosidase, whereas acidic sphingolipids (sulphatide, gangliosides GM1 and GD1a) incorporated into liposomes stimulated this enzyme only moderately (3-10-fold).
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PMID:Specificity of human glucosylceramide beta-glucosidase towards synthetic glucosylsphingolipids inserted into liposomes. Kinetic studies in a detergent-free assay system. 378 Jul 20

Extraction of control human spleen glucocerebrosidase with sodium cholate and butan-l-ol reversibly inactivates the enzyme in terms of its ability to hydrolyse the water-soluble substrate 4-methylumbelliferyl beta-D-glucopyranoside (MUGlc). The acidic brain lipid galactocerebroside 3-sulphate (sulphatide) reconstitutes beta-glucosidase activity in a strongly concentration-dependent manner. In this study we show that sulphatide exhibits three critical micellar concentrations (CMCs): CMC1, 3.72 microM; CMC2, 22.6 microM; CMC3, 60.7 microM. We designate the aggregates formed at these CMCs as primary, secondary and tertiary micelles respectively. From the results of kinetic studies performed at various sulphatide concentrations (0.012-248 microM), we found that sulphatide monomers (less than 3 microM) decreased the Km (for MUGlc) of control glucocerebrosidase from 11 to 4.6 mM, and lowered the Vmax. 2-fold. However, secondary and tertiary micelles were required for expression of high control glucocerebrosidase activities. Glucocerebrosidase prepared from the spleen of a patient with non-neuronopathic type 1 Gaucher's disease exhibited a very low Km (2.8 mM) even in the absence of exogenous lipid, and sulphatide monomers had no effect on the mutant enzyme's Km or Vmax. However, secondary or tertiary micelles markedly increased the Vmax. of the type 1 glucocerebrosidase to 60% of the corresponding control enzyme value. In contrast, for the glucocerebrosidase of the neuronopathic type 2 case, although sulphatide decreased the Km from 9.2 to 1.7 mM, the Vmax. never reached more than 5% that of the control enzyme, even at high concentrations of sulphatide. In addition, we found that secondary and tertiary sulphatide micelles enhanced the rate of inactivation of all three glucocerebrosidase preparations by chymotrypsin. Collectively, these results indicate the presence of two sulphatide-binding sites on glucocerebrosidase: one that enhances substrate binding, and another that enhances catalysis.
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PMID:A kinetic study of the effects of galactocerebroside 3-sulphate on human spleen glucocerebrosidase. Evidence for two activator-binding sites. 380 Sep 8


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