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)

Extracts of the pathogenic ameba Naegleria fowleri, prepared by freeze-thawing and sonication, were analyzed for their content of various hydrolytic enzymes that have acid pH optima. The organism is rich in acid phosphatase activity as well as a variety of glycosidases which include beta-glucosidase, beta-galactosidase, beta-fucosidase, alpha-mannosidase, hexosaminidase, arylsulfatase A, and beta-glucuronidase. The crude extract contained only negligible levels of sphingomyelinase, neuraminidase, or arylsulfatase B. All of the hydrolases exhibited higher activity at pH 5.5 than at 7.0, indicating that they are truly "acid" hydrolases. In general, after centrifugation (100,000 g, 1 h), except for arylsulfatase B, more than half of the activity of each of the various hydrolases was recovered in the supernatant fraction. The acid phosphatase in the high-speed supernatant was purified 45-fold (32% yield) by chromatography on QAE-Sephadex and Sephadex G-200 and shown to have the following properties: pH optima, 5.5; Km (4-methylumbelliferyl phosphate), 0.60 mM; molecular weight (estimated by gel filtration chromatography), 92,000; inhibited by heteropolymolybdate complexes but not by L(+) sodium tartrate (0.5 mM) or sodium fluoride (0.5 mM). In addition, unlike the tartrate-resistant acid phosphatase of Leishmania donovani, the major acid phosphatase of N. fowleri is less than 5% as effective in inhibiting superoxide anion production by f-Met-Leu-Phe-stimulated human neutrophils. The finding of high levels of a number of acid hydrolases in Naegleria fowleri raises several questions that merit further study: Do the hydrolases perform a housekeeping function in this single cell eukaryote or do they play some role in the pathogenic process that ensues when the organism infects a suitable host?
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PMID:Demonstration of various acid hydrolases and preliminary characterization of acid phosphatase in Naegleria fowleri. 301 38

The nephrotoxicity of three different dose levels of propyleneimine (10, 20 and 30 microliter/kg body wt) administered intraperitoneally to rats was studied and 20 microliters/kg body weight was found to be the most appropriate sublethal dose. Injection of propyleneimine (10 microliters/kg body wt) produced a small rise in N-acetyl-beta-D-glucosaminidase (NAG) activity, minor histological damage but no change in urine volume. Six rats were injected with 20 microliters/kg body weight, and urine was collected over the following 16 days. An immediate increase in urine volume, osmolality together with a concomitant decrease in specific gravity, was accompanied by a small increase in creatinine excretion and a more marked increase in the sodium and potassium content of urine after the administration of the nephrotoxin. NAG activity increased immediately and peaked on day 3, the activity remained elevated until day 12 when it fell to near normal levels. The activity of both beta-D-galactosidase and beta-D-glucosidase increased 9 days after administration of the nephrotoxin. In contrast, no consistent change was found in the excretion of the brush border marker enzymes, leucine aminopeptidase (LAP), alanine aminopeptidase (AAP) or alkaline phosphatase (ALP). Proteinuria increased sharply the day after injection and remained abnormal. Increased urinary albumin excretion and the predominance of low molecular weight proteins was demonstrated by sodium dodecyl sulphate (SDS) polyacrylamide gel electrophoresis. Evidence is presented that propyleneimine exerts its early toxic effect on the renal papilla.
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PMID:Renal toxicity of propyleneimine: assessment by non-invasive techniques in the rat. 309 1

1,4-beta-D-Glucan glucohydrolase (exo-1,4-beta-D-glucosidase) (EC 3.2.1.74) was isolated from growth supernatants of Torulopsis wickerhamii and was subjected to hydrodynamic, optical (CD), and kinetic analysis after purification to homogeneity by ammonium sulfate precipitation, size exclusion chromatography, ion exchange chromatography, and isopycnic banding centrifugation in cesium chloride. The last step was found to separate the enzyme from strongly associating, high molecular weight polysaccharide. Enzyme homogeneity was established by isoelectric focusing, sodium dodecyl sulfate-gel electrophoresis, and analytical high performance size exclusion chromatography using dual detection. The native exo-1,4-beta-D-glucosidase was found to be a dimer of 151,000 +/- 21,100 daltons by high performance size exclusion chromatography and 143,600 +/- 1,800 daltons by sedimentation equilibrium. The enzyme has a 12% linked carbohydrate content (mostly mannose) and no essential metal ions. Hydrolysis of p-nitrophenyl-beta-D-glucopyranoside was found to be optimal at pH 4.25 and 50 degrees C. The enzyme was found to produce beta-D-glucose from cellodextrins (indicating retention of anomeric configuration during hydrolysis) and demonstrated depolymerization from the non-reducing polymer terminus. The enzyme followed competitive type inhibition with p-nitrophenyl-beta-D-glucopyranoside as substrate and demonstrated high values of Ki for D-glucose and D-cellobiose inhibition (190 and 230 mM, respectively). The exo-1,4-beta-D-glucosidase was found to hydrolyze cellotetraose more rapidly than D-cellobiose and aryl-beta-D-glycosides more rapidly than all other substrates. Low levels of activity were found for the polymeric substrates beta-glucan (yeast cell walls), Avicel, and Walseth cellulose. Although this enzyme demonstrates broad disaccharide substrate specificity, a characteristic common to beta-D-glucosidases from many sources, the ability to hydrolyze higher cellodextrins more rapidly than cellobiose renders this enzyme the first exo-1,4-beta-D-glucosidase purified from yeast.
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PMID:Isolation and characterization of a 1,4-beta-D-glucan glucohydrolase from the yeast, Torulopsis wickerhamii. 309 75

The activity of the high-molecular-weight beta-glucosidase (beta-D-glucoside glucohydrolase, EC 3.2.1.21) obtained from culture filtrates of Botryodiplodia theobromae Pat. was affected by added NaCl in such a way that an initial phase of stimulation was followed by a phase of rapid non-linear decrease in velocity and finally by a phase of slow linear decrease in velocity as the concentration of NaCl was increased. In the presence of 0.014 M-sodium acetate/acetic acid buffer (pH 5.0) there was a slight increase in enzymic activity in the presence of low concentrations of dioxan (up to about 10% dioxan) and a rapid decrease in enzymic activity at higher dioxan concentrations, but both effects were mitigated in the presence of 0.1 M buffer. The order of efficiency of added glucosyl acceptors in beta-glucosidase-catalysed reactions was found to be fructose greater than sucrose greater than glycerol greater than methanol. The enzyme was inactivated by the active-site-directed compound conduritol-B-epoxide; but this inactivation was concentration-dependent, was prevented by 10 mM-glucose, and involved an acidic group with pKa 4.3. A rate equation has been derived on the assumption of a mechanism of action involving a solvent-separated and an intimate glucosyl cation-carboxylate ion-pair intermediate and an alpha-glucosyl enzyme intermediate [Umezurike, G. M. (1981) Biochem. J. 199, 203-209]. Calculations based on the application of the derived rate equation and the calculated kinetic parameters show that the rate equation explains the peculiar properties of beta-glucosidase in the presence of added glucosyl acceptors or of NaCl.
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PMID:The mechanism of action of beta-glucosidase from Botryodiplodia theobromae Pat. 310 76

We isolated two genes for extracellular beta-glucosidase, BGL1 and BGL2, from the genomic library of the yeast Saccharomycopsis fibuligera. Gene products (BGLI and BGLII) were purified from the culture fluids of Saccharomyces cerevisiae transformed with BGL1 and BGL2, respectively. Molecular weights of BGLI and BGLII were estimated to be 220,000 and 200,000 by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. The two beta-glucosidases showed the same enzymatic characteristics, such as thermo-denaturation kinetics and dependencies on pH and temperature, but quite different substrate specificities: BGLI hydrolyzed cellobiose efficiently, but BGLII did not. This result is consistent with the observation that the S. cerevisiae transformant carrying BGL1 fermented cellobiose to ethanol but the transformant carrying BGL2 did not. Southern blot analysis revealed that the two beta-glucosidase genes were derived from Saccharomycopsis fibuligera and that the nucleotide sequences of the two genes are closely related. The complete nucleotide sequences of the two genes were determined. BGL1 and BGL2 encode 876- and 880-amino-acid proteins which were shown to be highly similar to each other. The putative precursors begin with hydrophobic segments that presumably act as signal sequences for secretion. Amino acid analysis of the purified proteins confirmed that BGL1 and BGL2 encode BGLI and BGLII, respectively.
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PMID:Nucleotide sequences of Saccharomycopsis fibuligera genes for extracellular beta-glucosidases as expressed in Saccharomyces cerevisiae. 314 49

A 1,4-beta-D-glucan cellobiohydrolase (EC 3.2.1.91) and 1,4-beta-D-glucan glucanohydrolase (EC 3.2.1.4) were purified from the culture filtrates of Penicillium funiculosum by using preparative isoelectric focusing. Both the enzymes were homogeneous on polyacrylamide gel with and without sodium dodecyl sulphate. The mol wt of the cellobiohydrolase and endoglucanase were 14,400 and 25,000 respectively. The purified enzymes were free of beta-glucosidase activity. Acting in isolation, the cellobiohydrolase had little capacity for solubilizing Avicel or Walseth cellulose, but showed increased rates of hydrolysis when combined with endoglucanase. Cellobiose inhibition (50%) was observed in the initial rate of the hydrolysis of Walseth cellulose. It was also observed that cellobiohydrolase initiates the attack on crystalline cellulose.
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PMID:Mode of action and synergism of cellulases from Penicillium funiculosum. 322 93

The study of the acidic lipid requirement of human spleen glucocerebrosidase was extended to include two new series of acidic lipids, namely, monoacylglycol sulfates and diacylglycerol sulfates. Lysosomal glucocerebrosidase was extracted with sodium cholate and 1-butanol to render its beta-glucosidase activity dependent upon exogenous lipids. Maximum reactivation of control glucocerebrosidase was obtained with nonanoylglycol sulfate (NGS) and diheptanoylglycerol sulfate (DHGS). However, the effects of these lipids were markedly dependent on the nature of buffer used in the assay medium; specifically, 0.2 M sodium citrate-phosphate (pH 5.5) was much more effective than 0.2 M sodium acetate (pH 5.5) in permitting these lipids to reactivate glucocerebrosidase. In contrast, the marked activation of glucocerebrosidase by phosphatidylserine and galactocerebroside 3-sulfate (sulfatide) that was achievable in the sodium acetate buffer was totally inhibited by citrate or phosphate ions. The effects of NGS and DHGS on the kinetic parameters of control glucocerebrosidase were to lower the Km for the substrate, 4-methylumbelliferyl-beta-D-glucoside from 5.5 mM to approximately 2 mM (in sodium citrate-phosphate buffer) and markedly increase the Vmax. Furthermore, with DHGS, significant activation was achieved at concentrations below the lipid's critical micellar concentration. None of the monoacylglycol- or diacylglycerol sulfates were capable of stimulating mutant glucocerebrosidases from either type 1 (Ashkenazi-Jewish) or type 2 Gaucher's disease patients. Like control glucocerebrosidase, the type 1 glucocerebrosidase was unresponsive to phosphatidylserine and sulfatide when the beta-glucosidase assay was conducted in 0.2 M sodium citrate-phosphate buffer. Based on the differential action of these lipid activators in the two buffers and their effects on the mutant enzymes, we propose that, with regard to the lipid requirement of glucocerebrosidase, there are two classes of acidic lipids--one comprised of phosphatidylserine and sulfatide and the other comprised of the likes of NGS, DHGS, or sodium taurodeoxycholate. It appears that control glucocerebrosidase and the mutant enzyme of the patient with type 1 Gaucher's disease is reconstitutable with the first class of lipids whereas the glucocerebrosidase of the type 2 patient is not. The observations in this report are interpreted in terms of a model which postulates that normal glucocerebrosidase possesses at least two distinct lipid binding domains.
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PMID:Activation of human spleen glucocerebrosidases by monoacylglycol sulfates and diacylglycerol sulfates. 335 73

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

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

Male Sprague-Dawley rats were fed a purified fibre-free diet containing 5% (w/w) sodium saccharin for 4 weeks or 20 weeks and changes in caecal bacterial numbers and enzyme activities (endogenous ammonia production, beta-glucosidase, beta-glucuronidase, nitrate reductase, nitroreductase, aryl sulphatase) determined in vitro. Saccharin treatment gave marked caecal enlargement but had no effect on bacterial concentration at either treatment period, and significantly decreased beta-glucuronidase, nitrate reductase and sulphatase activities/g caecal contents. The incubation of a suspension of caecal contents from control rats with saccharin (75 mM) in vitro inhibited beta-glucuronidase and nitrate reductase activities, and ammonia production from endogenous substrates. Such changes may decrease the rate of formation of toxic bacterial products in the hindgut.
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PMID:Modification of rat caecal microbial biotransformation activities by dietary saccharin. 384 Feb 94


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