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)

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 condition for maximal activity (pH, buffer, saturating substrate concentration, range of linear relationships between enzyme activity versus incubation time, and versus enzyme concentration) in the fluorimetric assay of several glycohydrolases of lysosomal origin in human plasma and serum have been established. The following enzymes were studied: alpha-galactosidase, beta-galactosidase, beta-N-acetylglucosaminidase, beta-glucosidase, beta-glucuronidase, alpha-mannosidase, alpha-fucosidase. All examined enzymes turned out to be more or less unstable upon storage at 37 degrees C, 4 degrees c, and -20 degrees C in both serum and plasma. The only exceptions were beta-glucuronidase, which was stable in plasma and serum, and alpha-fucosidase which was stable only in plasma. Generally the degree of instability was greater in serum than in plasma. The levels of some enzymes (alpha-galactosidase, beta-galactosidase, beta-N-acetyl glucosaminidase, beta=glucuronidase) were markedly higher in serum than in plasma; conversely the levels of the same enzymes in "platelet free" serum equalled those in plasma. This stresses the necessity to use freshly prepared plasma for lysosomal glycohydrolase assay. Under the procedural conditions recommended for the assay the methods for the determination of lysosomal glycohydrolases in plasma appeared to be simple, sensitive and reproducible.
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PMID:Enzymes of lysosomal origin in human plasma and serum: assay conditions and parameters influencing the assay. 625 26

The enzyme activities of alpha-fucosidase (pH 4.0 and pH 5.5), alpha-galactosidase, beta-galactosidase, alpha-glucosidase (pH 4.5 and pH 6.0), beta-glucosidase, beta-glucuronidase, beta-hexosaminidase, and alpha-mannosidase (pH 4.5 and pH 5.5) were investigated in sera from cystic fibrosis (CF) patients. Several of these activities were significantly increased in sera from patients compared to age-matched control children. CF-patients in a more advanced stage of the disease had a tendency to higher values of some of these hydrolases than those in better condition. No new isoenzymes of these hydrolases were found. Only minor differences could be detected in the pH-profiles of alpha-mannosidase and acid phosphatase from age-matched normal controls, heterozygotes and homozygotes for CF. With our technique, alpha-mannosidase and acid phosphatase showed the same thermostability in CF-patients. CF-heterozygotes and age-matched controls, except at 56 degrees C, when the activity of acid-phosphatase in the plasma from adult CF-heterozygotes decreased more than that from adult controls
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PMID:Acid hydrolases in sera and plasma from patients with cystic fibrosis. 626 20

Castanospermine (1,6,7,8-tetrahydroxyoctahydroindolizine) was tested against a variety of commercially available glycosidases and found to be a potent inhibitor of almond emulsin beta-glucosidase, and also to inhibit fungal beta-xylosidase. This alkaloid was inactive on yeast alpha-glucosidase, alpha- or beta-galactosidase, alpha-mannosidase, beta-N-acetylhexosaminidase, beta-glucuronidase, alpha-L-fucosidase. Fifty-percent inhibition of beta-glucosidase required about 10 micrograms/ml of castanospermine. The amount of inhibition was uniform throughout the time course, and the inhibition with regard to substrate concentration (p-nitrophenyl-beta-D-glucopyranoside) appeared to be of the mixed type. Castanospermine was also a potent inhibitor of beta-glucocerebrosidase when assayed with fibroblast extracts using either a fluorimetric or a radioactive assay. Interestingly enough, castanospermine also inhibited the lysosomal alpha-glucosidase, and this inhibition required comparable levels of alkaloid to that required for inhibition of beta-glucocerebrosidase. However, a number of other lysosomal glycosidases were not sensitive to castanospermine (i.e., alpha- or beta-galactosidase, alpha- or beta-mannosidase, alpha- or beta-L-fucosidase, beta-N-acetylhexosaminidase, beta-glucuronidase).
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PMID:Castanospermine, a tetrahydroxylated alkaloid that inhibits beta-glucosidase and beta-glucocerebrosidase. 640 22

The activities of various glycosidases in homogenates of the small-intestinal mucosa of one adult and two suckling echidnas, Tachyglossus aculeatus, were investigated. The activities of lactase (beta-D-galactosidase), beta-N-acetylglucosaminidase, neuraminidase and alpha-L-fucosidase were higher in the sucklings than in the adult animal. Maltase and isomaltase activities were lower. Sucrase and cellobiase activities were absent or present in trace amounts only. The lactase activity had a pH optimum of 4.0-4.5, was predominantly in the soluble fraction following ultracentrifugation and was inhibited by p-chloromercuribenzene sulfonate, suggesting that it was due to a lysosomal acid beta-galactosidase and not a brush-border neutral lactase. The maltase activity of the sucklings also had the characteristics predominantly of a lysosomal acid hydrolase. It is proposed that in suckling echidnas, the oligosaccharides (mainly neuraminyllactose and fucosyllactose) of the mother's milk are digested intracellularly by lysosomal enzymes, rather than at the brush border, of the epithelial cells of the small-intestinal mucosa.
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PMID:Intestinal glycosidase activities in one adult and two suckling echidnas: absence of a neutral lactase (beta-D-galactosidase). 641 47

Fluorescent Pseudomonas species (P. aeruginosa, P. fluorescens, P. putida) were tested for the presence of glycosidase activities (alpha-D-glucosidase, beta-D-glucosidase, alpha-D-galactosidase, beta-D-galactosidase, beta-xylosidase, alpha-D-mannosidase, alpha-L-fucosidase, beta-L-fucosidase, beta-D-glucuronidase and N-acetyl-beta-D-glucosaminidase). Some of the investigated glycosidases were always absent, while N-acetyl-beta-D-glucosaminidase was constantly present in all strains; 3 glycosidase activities were observed in association or separately. Serotype O11 of P. aeruginosa was found to be homogeneous with respect to some of those enzymatic activities. Search for beta-D-galactosidase, alpha-D-glucosidase and beta-D-glucosidase may be of diagnostic value in epidemiologic studies of P. aeruginosa.
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PMID:[Detection of glycosidases in Pseudomonas of the fluorescent group: relation between serotype and glycosidase activities in P. aeruginosa]. 642 62

In platelets of subjects affected with myeloproliferative disorders the following lysosomal enzymes were studied: alpha-mannosidase, alpha-fucosidase, beta-galactosidase, beta-glucosidase, beta-glucuronidase, beta-N-acetylglucosaminidase and acid phosphatase. For each enzyme the specific activity, the optimum of pH and buffer, Km and saturating substrate concentrations, as well as thermostability were determined. Control and patient enzymes showed no difference.
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PMID:Platelet lysosomal enzymes are normal in myeloproliferative disorders. 643 83

The optimal assay conditions and the levels of seven lysosomal glycohydrolases (alpha-D-galactosidase, beta-D-galactosidase, beta-D-glucosidase, beta-D-glucuronidase, beta-N-acetyl-D-glucosaminidase (2-acetamido-2-deoxy-beta-D-glucoside acetamidodeoxyglucohydrolase), alpha-D-mannosidase, alpha-L-fucosidase) were determined in human peripheral unseparated lymphocytes, T and non-T lymphocyte subpopulations. From fifteen adult volunteers the enzymes were assayed by fluorimetric procedures using the corresponding 4-methylumbelliferyl glycosides as substrates. The enzyme assay procedures displayed good precision and reproducibility. All the tested enzymes had higher activities in non-T than T lymphocytes. This difference was statistically highly significant, especially when the enzyme contents were expressed on a DNA, rather than mg protein, basis. Unseparated lymphocytes displayed levels of lysosomal enzymes which corresponded to the proportion of T and non-T lymphocytes in the unseparated preparation, indicating that the process of lymphocyte fractionation caused neither loss nor activation of lysosomal enzymes. It is concluded that the observed difference in lysosomal enzyme levels is an authentic imprint of the two lymphocyte subpopulations, implying a differential role played by the lysosomal apparatus in the same cells.
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PMID:Lysosomal glycohydrolases in normal T and non-T peripheral lymphocytes. 660 89

Human tumor cells of neurectoderm origin contain a high proportion of alpha-L-fucosyl linkages were determined by high-resolution, 500-MHz, 1H-n.m.r. spectroscopy which gave signals characteristic for alpha-L-Fucp-(1 leads to 3)-D-GlcNAc residues these L-fucosyl residues. This was shown by use of a specific alpha-L-fucosidase from almond emulsin and a broad-spectrum alpha-L-fucosidase from rat testes. The exact alpha-L-fucosyl linkages were determined by high-resolution, 500-MHz, 1H-n.m.r. spectroscopy which gave signals characteristic for alpha-L-Fucp-(1 leads to 3)-D-GlcNAc residues linked to branches and for alpha-L-Fucp-(1 leads to 6)-D-GlcNAc residues linked to the core. More than 95% of the asparagine-linked GlcNAc residues were substituted with (1 leads to 6)-alpha-L-fucosyl groups. Further definition of the range of neutral glycopeptides was obtained with immobilized lectins. Binding to E-PHA-agarose suggested the presence of a beta-D-mannopyranosyl residue substituted at O-4 by a 2-acetamido-2-deoxy-D-glucopyranosyl group. alpha-L-Fucp-(1 leads to 3)-GlcNAc interfered with this binding since removal of alpha-L-fucosyl groups by almond emulsin alpha-L-fucosidase increased the binding by 100%. These studies demonstrate the ability of a combination of high-resolution 1H-n.m.r., enzyme degradation, and lectin-binding affinities to delineate structural elements of small amounts of oligosaccharide residues.
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PMID:Characterization of the neutral glycopeptides containing the structure alpha-L-fucopyranosyl-(1 leads to 3)-2-acetamido-2-deoxy-D-glucose from human neuroblastoma cells. 662 47

The activities of various glycosidases in homogenates of the small intestinal mucosa of two adult and 18 suckling tammar wallabies (M. eugenii) aged from 6 to 50 weeks were investigated. Lactase (beta-D-galactosidase), beta-N-acetylglucosaminidase, alpha-L-fucosidase and neuraminidase activities were high during the first 34 weeks post partum and then declined to very low levels. Maltase, isomaltase, sucrase and trehalase activities were very low or absent during the first 34 weeks, and then increased. The lactase activity was unusual in being greater in the distal than the middle or proximal thirds of the intestine, and in its low pH optimum (pH 4.6), inhibition by p-chloromercuribenzene sulfonate but not by Tris, and lack of cellobiase activity. These properties are those of a lysosomal acid beta-galactosidase rather than of a brush border neutral lactase. The maltase activity had the characteristics of a lysosomal acid alpha-glucosidase early in lactation and of a brush border neutral maltase in adult animals. The significance of these findings is discussed in relation to changes in dietary carbohydrates during weaning and to the mode of digestion of milk carbohydrates by the pouch young.
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PMID:Intestinal lactase (beta-galactosidase) and other glycosidase activities in suckling and adult tammar wallabies (Macropus eugenii). 678 21


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