Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.20 (alpha-glucosidase)
 4,237 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Glycosidase activities in the adults and juveniles of the lung fluke Paragonimus ohirai and P. westermani adults were demonstrated histochemically. For comparative studies, histochemical examination was also made on the adults of the liver fluke Fasciola hepatica. The enzymes examined were N-acetyl-beta-glucosaminidase (EC 3.2.1.30), beta-glucuronidase (EC 3.2.1.31), beta-galactosidase (EC 3.2.1.23), alpha-glucosidase (EC 3.2.1.20) and beta-glucosidase (EC 3.2.1.21). The distribution of beta-glucosaminidase was similar in juveniles and adults. Strong reaction sites for the enzyme were the caecal brush border, tegument, subtegumental cells and tests. In contrast, no staining reaction occurred in the caeca of F. hepatica, although the tegument and parenchymal cells were weakly stained. beta-glucuronidase activity was associated only with the luminal surface of the caeca in the juveniles. However, luminal contents also appeared stained and this might suggest that the activity in the caeca is not endogenous. beta-galactosidase was localized in the caeca, sub-tegmental cells and tegument in both juveniles and adults. No reaction occurred for the other two enzymes, alpha- and beta-glucosidase.
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PMID:Histochemical studies of glycosidase activity in juveniles and adults of the lung fluke Paragonimus. 622 Feb 58

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

3-O-Methyl-D-glucose (3-O-MeGlc) or a mixture of 3-O-MeGlc and glucose stimulate invertase, beta-glucosidase, alpha-glucosidase, and alpha-galactosidase production by Cryptococcus laurentii. They also increase invertase and alpha-glucosidase production by Saccharomyces cerevisiae. The stimulatory effect of 3-O-MeGlc is not caused by competition with glucose for transport nor by a direct action on glycosidases. It is proposed that 3-O-MeGlc acts as a structural rather than as a functional analogue of glucose displacing it from regulatory sites to relieve catabolite repression. Evidence is presented suggesting that intracellular cAMP levels may be related to the effect of 3-O-MeGlc.
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PMID:Effect of 3-O-methyl-D-glucose on the production of glycosidases by Cryptococcus laurentii and Saccharomyces cerevisiae. 626 Mar 20

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

In order to characterize lactase/beta-glucosidase and the neutral alpha-glucosidase kinetically in the brush border membrane at different villus sites of normal human jejunal mucosa, a quantitative histochemical study has been carried out on biopsy specimens of patients only suffering from functional disturbances revealing normal mucosal architecture. The apparent Vmax-values of both alpha- and beta-glucosidases increased significantly from the villus base to the transition zone between medium and apical villus third. During enterocyte maturation on the villus no changes in the apparent Km-values could be detected. Equally the ratios between the Vmax-values of the disaccharidases remained constant. Male persons exhibited significantly greater apparent Vmax-values for alpha-glucosidase than females at both villus measuring positions. The findings can be taken as a starting point for the evaluation of local changes of apparent enzyme-kinetic data under pathological conditions.
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PMID:"In situ" determinations of apparent Km and Vmax of brush border disaccharidases along the villi of normal human jejunal biopsy specimens. A quantitative histochemical study. 626 80

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 "in situ" kinetic constants (app. Km and Vmax) of brush border neutral alpha-glucosidase (EC 3.2.1.20) and lactase/beta-glucosidase (EC 3.2.1.21) were determined 4,6 (only alpha-glucosidase), and 12 days after 60% proximal intestinal resection in rat ileum at the villus base and the transition zone between middle and upper villus third by use of a quantitative biochemical analysis of enzymes in tissue sections (section biochemistry). Sham-operated rats served as controls, and the kinetic data (means per rat, time and villus position) were compared (n = 4 animals in each experimental group) first by an overall factorial analysis of variance and thereafter in detail using nonparametric test procedures. Both enzyme activities exhibited a differential response: No changes of lactase/beta-glucosidase kinetics, but a significant decrease in both Vmax- and Km-values of neutral alpha-glucosidase, which was already fully expressed on day 4 after resection and confined to the apical villus region still implying a basoapical increase of Vmax and thus maintaining the normal activity gradient on a lower level. In conclusion, a complex pattern of enzymatic adaptation to proximal intestinal resection ensues in the hyperplastic ileal mucosa which cannot be explained simply in terms of the hypothesis of cellular immaturity.
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PMID:The adaptive response of disaccharidase activities at different sites along the villus epithelium after proximal intestinal resection in the rat. A microdensitometric study of enzyme kinetics. 641 38

In order to study the influence of biliary secretions on the in situ kinetic data of brush border disaccharidases in relation to small intestinal villus-crypt architecture, an anastomosis was constructed between the common bile duct, which had been divided before its entrance into the pancreatic head, and the ileum in adult female Wistar rats. Simple attachment of the terminal ileum to the liver hilum was performed in the controls. Six weeks after the operation, tissue sections were prepared from duodenum and ileum of biliary-diverted and control animals (n = 5 in each group) and examined by section biochemistry and morphometry. In both groups the apparent Vmax values of neutral alpha-glucosidase and lactase/beta-glucosidase, measured at the villus base and at its apex, and the villus height were decreased from the duodenum towards the distal ileum. After biliary diversion to the ileum, an increase in villus height ensued in this segment, and the increasing gradient of glucosidase activity towards the villus apex, as seen in the ileum of the controls, was no longer detectable. In the duodenum, however, villus height remained unaltered and the in situ activity of the disaccharidases was increased at both villus sites when compared with the controls. The results indicate different effects of bile on mucosal morphology and function in the proximal and distal small intestine.
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PMID:Effects of biliary diversion to the ileum on the in situ disaccharidase activities of duodenal and ileal mucosa in the rat: a study on enzyme kinetics in tissue sections. 641

Mouse peritoneal macrophages that had been treated with a monovalent carboxylic ionophore, monensin, selectively secreted lysosomal and nonlysosomal granular enzymes into the medium. When macrophages were incubated with 1 to 10 microM monensin, the release of beta-glucuronidase, beta-hexosaminidase and beta-galactosidase was stimulated time and does dependently. Neither the beta-glucosidase nor acid phosphatase, enzymes bound to the lysosomal membranes, however, were released by monensin. Neutral alpha-glucosidase, shown recently to be localized in nonlysosomal granules of macrophages (15), was released by monensin at concentrations lower than those required for lysosomal enzyme release. Increased release of lysosomal enzymes also took place in a manner similar to that seen with monensin-treated macrophages after treatment of macrophages with weak bases, chloroquine and ammonium chloride. Neutral alpha-glucosidase, however, was not released when chloroquine was present in concentrations that stimulated the release of lysosomal enzymes. The UDP-galactosyltransferase activity of the Golgi apparatus in the macrophages markedly decreased after treatment with low concentration of monensin.
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PMID:Stimulation of the release of lysosomal and nonlysosomal granular enzymes from macrophages treated with monensin. 643 21

The activity of acid hydrolases was studied in serum from patients with mucolipidosis (II and III) and other lysosomal disorders. In mucolipidosis II and III all hydrolases examined except alpha-glucosidase, beta-glucosidase and acid phosphatase were greatly increased. High values for beta-galactosidase were seen in mucopolysaccharidosis types I and II, Gaucher's disease, juvenile amaurotic idiocy and metachromatic leucodystrophy. N-Acetyl-beta-glucosaminidase activity was high in mucopolysaccharidosis types I, II, III and Gaucher's disease. The activity of beta-glucuronidase was increased in mucopolysaccharidosis types I, II and III, Gaucher's disease, juvenile amaurotic idiocy and metachromatic leucodystrophy. Acid phosphatase had increased activity only in Gaucher's disease. In several lysosomal storage disorders no increased values could be found. It is suggested that high values in serum from patients with lysosomal storage disorders (not including mucolipidosis II and III) may depend upon liver cell damage, which disturbs the clearing of acid hydrolases from serum.
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PMID:Acid hydrolases in serum from patients with lysosomal disorders. 676 92


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