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)

An enzyme, which lacks cellobiase activity, responsible for the synthesis of ethyl-beta-glucoside has been found in the extracts of pea hooks (1-centimeter length of the apical portion of epicotyl) and has been partially purified by ammonium sulfate fractionation. The enzyme can transfer the glucosyl moiety from a group of phenolic beta-glucosides to ethanol. A specific beta-glucosyl donor, isosuccinimide beta-glucoside, isolated from the extracts of pea seedlings shows the highest activity. The characteristics of the enzyme which synthesizes ethyl-beta-glucoside and the glucosyl donor, isosuccinimide beta-glucoside, have been studied. The significance of this system (enzyme and isosuccinimide beta-glucoside) has been discussed.
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PMID:The biosynthesis of ethyl-beta-glucoside in extracts of pea seedlings. 542 11

Two strains of Saccharomyces lactis (Y-14 and Y-1057A), medium (B(m)) and low (B(1)) constitutive producers of beta-glucosidase, were grown in enriched medium. beta-Glucosidase was extracted by autolysis and purified by ammonium sulfate precipitation, gel filtration, and calcium phosphate gel adsorption-elution. The kinetics of release, purification, and stability of beta-glucosidase from strains Y-14 and Y-1057A were compared with the enzyme from strain Y-123. The ability of glycerol, sorbitol, and mannitol to stabilize the beta-glucosidases is presented. A lower molecular weight, labile form of the Y-14 enzyme is demonstrated. Differences in the initial specific activites of beta-glucosidase among the three strains are discussed.
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PMID:Purification of beta-glucosidase from Saccharomyces lactis strains Y-14 and Y-1057A. 568 96

Constitutive beta-glucosidases from Saccharomyces fragilis (Y-18) and S. dobzhanskii (Y-19) precipitated at the same concentration of ammonium sulfate. The partially purified enzymes had similar activation energies, molecular weights, affinities for certain natural and synthetic beta-glucosides, and optimal pH values for substrate hydrolysis, and they were stable over approximately the same pH range. The enzymes, however, could be clearly distinguished by other criteria. Affinities of the synthetic, sulfur-containing beta-glucosides for Y-18 enzyme were many times greater than for Y-19 enzyme. The latter enzyme was more resistant to heat. The two enzymes eluted from diethylaminoethyl cellulose at different concentrations of sodium chloride. In precipitin tests, homologous enzyme-antisera systems were highly specific. The beta-glucosidase synthesized by a hybrid, S. fragilis x S. dobzhanskii (Y-42), was unique. Characterization of this enzyme produced values which were intermediate to those for the enzymes from the parental yeast strains. Heat-inactivation slopes and Lineweaver-Burk plots for the Y-42 enzyme were anomalous. It is suggested that hydrolytic activity in Y-42 preparations is due to a spectrum of hybrid enzyme molecules composed of varying amounts of two distinct polypeptides. It is further suggested that these polypeptides may be identical to those synthesized by the parental Y-18 and Y-19 yeast strains.
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PMID:Purification and characterization of yeast beta-glucosidases. 602 Apr

Lysosomal enzymes of the slime mold Dictyostelium discoideum contain mannose 6-phosphate and bind with high affinity to the phosphomannosyl receptor of human fibroblasts. In this study, we have partially characterized the Asn-linked oligosaccharide units present on these enzymes. [3H]Mannose-labeled alpha-D-mannosidase, beta-D-glucosidase, and beta-D-N-acetylglucosaminidase were purified from the spent growth medium of strain AX3 and glycopeptides were prepared by pronase digestion. Approximately 75% of the glycopeptides contained sulfate residues. These could be removed by solvolysis without degrading the underlying oligosaccharide. Following solvolysis (but not before), the oligosaccharides could be released by endo-beta-N-acetylglucosaminidase H, indicating the presence of high mannose-type units. Greater than 85% of the oligosaccharides contained one or two mannose 6-phosphate residues in the form of an unusual acid-stable phosphodiester. About 3% of the oligosaccharides contained phosphomonoesters and only 6% were neutral species. The major neutral oligosaccharide eluted in the position of Man9GlcNAc when analyzed by high performance liquid chromatography whereas the minor species appeared to be 1-2 residues larger. Acetolysis of the major phosphorylated fractions revealed that molecules with a single mannose 6-phosphate contained the phosphomannosyl residue on the branch linked alpha 1,6 to the beta-linked mannose whereas molecules with two phosphomannosyl residues had the residues on this branch as well as the branch linked alpha 1,3 to the beta-linked mannose. The mechanism of mannose phosphorylation in the slime mold must differ from that of mammalian cells since the phosphomannosyl residues are present as acid-resistant phosphodiesters rather than acid-labile phosphodiesters.
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PMID:Structural analysis of the asparagine-linked oligosaccharides from three lysosomal enzymes of Dictyostelium discoideum. Evidence for an unusual acid-stable phosphodiester. 622 51

Six glycoside hydrolases in the culture medium of Bacteroides fragilis--alpha-glucosidase, beta-glucosidase, alpha-galactosidase, beta-galactosidase, beta-N-acetylglucosaminidase, and alpha-L-fucosidase-were systematically purified by ammonium sulfate precipitation, gel filtration chromatography, and density gradient isoelectric focusing. The isoelectric focusing resolved the glycosidases into distinct, well-separated fractions and revealed three differently charged forms of beta-N-acetylglucosaminidase and of alpha-L-fucosidase. Furthermore, alpha-glucosidase and beta-N-acetylglucosaminidase were shown to possess dual affinities for the respective galactoside substrates, and beta-galactosidase also hydrolyzed beta-D-fucoside. alpha-Glucosidase was purified to homogeneity, as indicated by a thin-layer isoelectric focusing zymogram technique. The glycosidases, with exception of beta-glucosidase and the acid alpha-L-fucosidase, were each separated from other glycosidic activities to 99%. The molecular weights varied between 58,000 and 125,000. The pH optima ranged from 4.8 to 6.9.
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PMID:Purification of glycoside hydrolases from Bacteroides fragilis. 625 Apr 77

The immature sugar cane stalks studied contained less than 7% sucrose, and showed the activities of enzymes such as invertase, alpha-galactosidase, alpha-mannosidase, beta-N-acetylglucosaminidase, beta-glucosidase, beta-xylosidase, and beta-galactosidase. The alpha-galactosidase was highly purified by ammonium sulfate fractionation, gel filtration on a Sephadex G-100 column, ionexchange chromatography on DEAE-cellulose, and CM-cellulose columns, and heat treatment (60 degrees C, 15 min) in the presence of 0.2 m D-galactose. In polyacrylamide gel electrophoresis, the purified enzyme was homogeneous, having a molecular weight of approximately 46,000. In gelfiltration, it was approximately 47,000. The activity was optimum at pH 4.5 and at 60 degrees C. The purified enzyme hydrolyzed p-nitrophenyl-alpha-D-galactopyranoside (Km, 0.83 mM; Vmax, 25.0 mumol/mg/min), raffinose (Km, 25.9 mM; Vmax, 15.4 mumol/mg/min), and stachyose (Km, 13.0 mM; Vmax 2.7 mumol/mg/min), in addition to melibiose, guar gum, and locust bean gum. The hydrolysis of p-nitrophenyl-alpha-D-galactopyranoside was markedly inhibited by HgCl2, AgNO3, p-chloromercuribenzoate (PCMB), L-ascorbic acid, melibiose, stachyose, and D-galactose. Also the purified enzyme showed a lectin activity with trypsinized erythrocytes.
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PMID:Purification and properties of alpha-galactosidase from immature stalks of Saccharum officinarum (sugar cane). 627 79

A new, weakly hydrophobic, high-performance liquid chromatography column has been developed for the separation of native proteins based on their relative hydrophobicities. Starting with a covalently bound, hydrophilic polyamine matrix, packing materials were synthesized through acylation with anhydrides and acid chlorides of increasing chain length to obtain increasingly hydrophobic surfaces. Proteins in aqueous buffers were induced to bind hydrophobically to the columns by the use of high salt concentrations in the mobile phase. Elution was achieved by decreasing the ionic strength of the solvent in a linear gradient. A mixture of cytochrome c, conalbumin, and beta-glucosidase was used as a standard to test the resolving power of newly synthesized columns. On a 4-cm butyrate column, baseline resolution was achieved in 20 min with a gradient of 3.0 mu sodium sulfate in 0.1 M potassium phosphate buffer, pH 7.0, to water. The static loading capacity for each column was determined using a hemoglobin binding assay. Capacities normally ranged between 150 and 180 mg of hemoglobin per gram of support. Since proteins are not denatured in hydrophobic interaction chromatography, enzymes eluted from the column retained enzymatic activity. Samples of alpha-amylase and beta-glucosidase ranging in size from 10 to 200 micrograms were recovered from the butyrate column with greater than 92% enzymatic activity in all cases. In a single trial, the enzyme citrate synthase was recovered from the benzoate column with 92% retention of enzymatic activity.
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PMID:High-performance hydrophobic interaction chromatography of proteins. 642 67

Homogeneous (as judged by data from gel filtration, ultracentrifugation, polyacrylamide gel electrophoresis with and without sodium dodecyl sulfate (SDS), and isoelectric focusing) beta-xylosidase showing beta-D-xylosidase, beta-D-glucosidase, beta-D-galactosidase, and alpha-L-arabinosidase activities has been isolated from the hemicellulase preparation of the microscopic fungus Aspergillus niger 15 by ethanol fractionation and chromatography on Sephadex G-50, cellulose DE-52, and Sephadexes SP C-50 and G-200. The specific activity of the enzyme toward p-nitrophenyl-beta-D-xylopyranoside (p-NPX) increased 199-fold and was equal to 35.2 units/mg of protein; the activity yield was 43%. The sedimentation coefficient was equal to 10.6 S, and the molecular weight was 253,000 according to the gel filtration data and 122,000 according to the data from SDS electrophoresis. The isoelectric point was at pH 4.9. An amino acid analysis has shown that dicarboxylic and hydrophobic amino acids prevail in the enzyme. beta-Xylosidase had no carbohydrate component, and p-chloromercuribenzoate inhibited its activity. The temperature optimum of beta-xylosidase activity toward p-NPX was at 70 degrees C, and the pH optimum was 3.8-4.0. The enzyme was stable at pH 3 to 8 and did not lose its activity for 1 h at temperatures up to 50 degrees C. D-Xylose was found to be a competitive inhibitor of the beta-D-xylosidase activity of the enzyme with Ki = 2.9 mM. beta-Xylosidase showed transglycosylase activity.
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PMID:beta-Xylosidase from Aspergillus niger 15: purification and properties. 643 8

Two Sepharose-bound substrate analogs, 6'-aminohexanoyl-(2-N-sphingosyl-O-beta-D-glucoside) and 6'-aminohexyl-dodecanedioyl-1-(2-N-sphingosyl-1-O-beta-D-glu coside), were synthesized and used sequentially for the affinity purification of lysosomal beta-glucosidase (N-acyl-sphingosyl-1-O-beta-D-glucoside:glucohydrolase, EC 3.2.1.45). The capacities of these nondegradable affinity supports were 0.1 and 0.15 mg enzyme/ml settled gel, respectively. The purified enzyme had a specific activity of 75 mumol min-1 mg-1. The preparation had a single protein band with a molecular weight of 67,000 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, evidencing its apparent homogeneity. Isoelectric focusing on granular gels revealed four molecular forms of the enzyme with pI values of 4.0, 4.5, 4.7, and 5.8 to 6.2. The purified enzyme hydrolyzed glucosyl ceramide and 4-methylumbelliferyl-beta-D-glucoside with Km and Vmax values of 0.6 and 2.5 mM, and 101 and 26.1 mumol min-1 mg-1, respectively. The enzyme also hydrolyzed octyl beta-glucoside, a linear mixed-type inhibitor of the enzyme. Binding constants (Ki) were determined for the inhibitors, sphingosyl-1-O-beta-D-glucoside (Ki = 20 microM) and its N-hexyl derivative (Ki = 0.3 microM). The enzyme had a half-life of 65 and 30 min at 50 degrees C and pH 5.0 or 6.0, respectively. In addition, two other classes of ligands were used for the purification of lysosomal beta-glucosidase, and their capacities and specificities were compared to those of the substrate analog affinity supports. These included (i) the alkyl amine inhibitors octylamine, decylamine, and tetradecylamine; and (ii) the inhibitors, 6-aminohexanoyl-beta-glucosylamine and aminododecanoyl-1-(2-N-sphingosyl-1-O-beta-D-glucoside). Compared to these other ligand columns, the substrate analog affinity supports had about 100- to 1000-fold greater capacities or afforded 8- to 40-fold greater purification of human lysosomal beta-glucosidase.
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PMID:Human lysosomal beta-glucosidase: purification by affinity chromatography. 643 71

A peptide N-glycosidase that catalyzes the hydrolysis of N-linked oligosaccharide chains from glycopeptides and glycoproteins has been purified to homogeneity from almond emulsin and from almond meal. Purification from almond emulsin using ion-exchange chromatography, gel filtration chromatography, and preparative polyacrylamide gel electrophoresis gave an enzyme which was purified more than 700-fold and with a yield of 63%. An alternative procedure, more suitable for efficient large scale purification, used ion-exchange, affinity, and gel filtration chromatography. When purification began with almond emulsin, the enzyme was purified 1200-fold with a 37% yield, while when purification began with almond powder, the enzyme was purified 9000-fold with a yield of 45%. The homogeneous enzyme is stable at 4 degrees C for several months in 10 mM sodium acetate, pH 5.0, buffer. The peptide N-glycosidase is itself shown to be a glycoprotein consisting of a single polypeptide chain with a molecular weight of 66 800 on sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis. Circular dichroism spectra of the native molecule indicate the presence of a high (approximately 80%) alpha-helix content. The amino acid and carbohydrate contents of the enzyme are presented. When a convenient new assay with a turkey ovomucoid glycopeptide as a substrate is used, the enzyme preparation exhibits a broad pH optimum centered between pH 4 and pH 6. The enzyme is readily inactivated by SDS and guanidine hydrochloride, but it is stable in the presence of moderate concentrations of several other protein denaturants.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Structural and chemical characterization of a homogeneous peptide N-glycosidase from almond. 671 26


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