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)

1,2:5,6-Di-O-isopropylidene-D-glucitol was converted via its 1,4-dimethanesulfonate into the 1-azido-4-methanesulfonate which, after deprotection and treatment with barium hydroxide, afforded a 9:1 mixture of the corresponding 3,4- and 4,5-anhydro derivatives. Reduction of this mixture by transfer hydrogenation using ammonium formate in methanol and Pd/C as catalyst afforded 1,4-dideoxy-1,4-imino-D-glucitol (4), the structure of which was proved after acetylation by 1H-n.m.r. spectroscopy. Compound 4 is a potent alpha-D-glucosidase inhibitor (Ki 7 X 10(-4)M) and a less potent beta-D-glucosidase inhibitor (Ki 1.25 X 10(-4)M), and inhibits beta-D-galactosidase non-competitively.
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PMID:Synthesis of 1,4-dideoxy-1,4-imino-D-glucitol, a glucosidase inhibitor. 309 67

The chemical synthesis of swainsonine [(1S,2R,8R,8 alpha R)-trihydroxyindolizidine] from trans-1,4-dichloro-2-butene was previously described [Adams, C. E., Walker, F. J., & Sharpless, K. B. (1985) J. Org. Chem. 50, 420-424]. A modification of that synthesis provided two other isomers, referred to here as "Glc-swainsonine" [(1S,2S,8R,8 alpha R)-trihydroxyindolizidine] and "Ido-swainsonine" [(1S,2S,8S,8 alpha R)-trihydroxyindolizidine]. To determine whether these new compounds had biological activity, they were compared to swainsonine as inhibitors of a number of commercially available glycosidases. While swainsonine is a potent inhibitor of jack bean alpha-mannosidase but does not inhibit other glycosidases, its two isomers were inactive on alpha-mannosidase but did inhibit other enzymes. Thus, Glc-swainsonine was an inhibitor of the fungal alpha-glucosidase amyloglucosidase, and this inhibition was of a competitive nature (Ki = 5 X 10(-5) M) with respect to the substrate p-nitrophenyl alpha-D-glucopyranoside. This alkaloid also inhibited beta-glucosidase, but much less effectively than alpha-glucosidase. On the other hand, Ido-swainsonine was more effective toward beta-glucosidase than toward alpha-glucosidase, and this inhibition was also of a competitive nature. None of these inhibitors were effective against beta-mannosidase or alpha- or beta-galactosidase. Glc-swainsonine was also tested against the glycoprotein processing glycosidases. Surprisingly, in this respect, the alkaloid was like swainsonine in that it inhibited mannosidase II but had no effect or only slight effect on glucosidase I, glucosidase II, and mannosidase I. Glc-swainsonine also inhibited glycoprotein processing in cell culture.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of isomers of swainsonine on glycosidase activity and glycoprotein processing. 311 29

1. The intestinal disaccharidase activities of a suckling crabeater seal were investigated. 2. Lactase, maltase, isomaltase and cellobiase activities were readily detected but trehalase and sucrase activities were absent. 3. The intestinal homogenates were separated into a soluble (S2) fraction and a particulate brush border (P2) fraction. The lactase activities of the two fractions had different properties corresponding to those of an acid and a neutral beta-galactosidase respectively. Approximately two-thirds of the total lactase activity measured at pH 6.0 was due to the acid beta-galactosidase. 4. The isomaltase and cellobiase activities were found almost exclusively in the particulate fractions but about one third of the maltase activity was in the S2 fraction. This soluble maltase activity appeared to be due to an acid maltase.
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PMID:Intestinal lactase and other disaccharidase activities of a suckling crabeater seal (Lobodon carcinophagus). 313 70

Electron inactivation analysis with 16 MeV electrons was used to determine the functional target size of a number of commonly studied lysosomal hydrolases. Observed values ranged from a low of 62 000 +/- 4000 Da for beta-galactosidase to a high of 200 000 +/- 17 500 Da (mouse beta-glucuronidase). One group of lysosomal hydrolases (N-acetyl-beta-glucosaminidase, N-acetyl-beta-galactosaminidase, alpha-galactosidase, beta-mannosidase, beta-glucosidase, arylsulphatase A and sphingomyelinase) had target sizes in the range 100 000-120 000 Da, whereas alpha-glucosidase and alpha-fucosidase exist as complex multimers in the 150 000-160 000 Da range. Analysis of freeze-dried cell material showed little evidence of species (mouse versus human) variation in the functional size of most lysosomal hydrolases with the exception of beta-glucuronidase. Our findings suggest the potential usefulness of lysosomal hydrolases as endogenous marker enzymes in studies where the target size of proteins of unknown molecular mass is to be determined.
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PMID:Functional lysosomal hydrolase size as determined by radiation inactivation analysis. 315 87

Assay conditions were studied for eleven lysosomal enzymes (beta-D-galactosidase, alpha-D-mannosidase, beta-hexosaminidase, beta-D-glucuronidase, alpha-D-galactosidase, alpha-D-glucosidase, arylsulfatase, beta-D-glucosidase, alpha-L-fucosidase, alpha-D-neuraminidase and alpha-L-iduronidase) in cultured amniotic fluid cells (CAFC), cultured skin fibroblasts (CSF) and cultured embryonic lung fibroblasts (CELF), and the properties of the enzymes were compared among these cultured cells. In addition, changes in these enzymes from the three cell types were investigated between 4-6 earlier passages and 24-26 later passages. With the exception of alpha-D-glucosidase, alpha-D-neuraminidase and alpha-L-fucosidase, all enzymes assayed for the 4-6 earlier passages and the 24-26 later passages had the same Km values and the same pH optima, and were also unchanged with the increasing age of cell cultures, with regard to their points. The specific activities of beta-D-glucuronidase, arylsulfatase, alpha-D-glucosidase and beta-D-glucosidase for the 4-6 earlier passages increased significantly with development, though no change was observed with development in the specific activities of other enzymes. Variations were observed between the levels of these enzymes in the three cell types with the increasing age of cell cultures, such as increases in some, decreases in others and no change in still others.
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PMID:Comparative enzymology of eleven acid hydrolases in cultured amniotic fluid cells, skin fibroblasts and embryonic lung fibroblasts, and the respective changes with the increasing age of the cell cultures. 316 Dec 15

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

The interactive effects of lima bean trypsin inhibitor (TI), hemagglutinin (Hgg) and cyanide (CN) when fed at the same degree of activity as found in the raw lima bean (RLB) were assessed in weanling rats using hepatic glutamate dehydrogenase (GLDH), isocitrate dehydrogenase (ICDH), ornithine carbamoyltransferase (OCT) and intestinal disaccharidases activities as the response criteria. Whereas RLB significantly (P less than 0.05) increased hepatic GLDH and decreased ICDH activities respectively, dietary CN, TI and Hgg whether acting individually or jointly had no significant influence on GLDH. Only the CN-containing diets significantly (P less than 0.05) elevated ICDH activity when compared with the control. Raw lima bean significantly (P less than 0.05) depressed OCT activity while neither the individual nor collective effects of these factors were significant. Dietary CN + TI + Hgg interaction depressed maltase activity to approximately the same extent as RLB in all the intestinal regions. These factors had neither individual nor collective effects on sucrase in the small intestine. Lactase activity in the small intestine was influenced only by the RLB diet, while CN + Hgg, and CN + TI + Hgg dietary combinations induced significant (P less than 0.05) elevations in the activities of cellobiase when compared with the control. Although synergism of action is indicated in a number of instances, it is suggested that these factors may need to combine with others within the bean, perhaps synergistically, to elicit comparable anti-nutritional influences as the RLB.
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PMID:The interactive effects of lima bean (Phaseolus lunatus) trypsin inhibitor, hemagglutinin and cyanide on some hepatic dehydrogenases, ornithine carbamoyltransferase and intestinal disaccharidases in weanling rats. 324 17

Serum antinuclear antibodies were induced in rats by treatment with hydralazine or todralazine, given in daily dose of 25 mg/kg of body wt. for 12 months. An increased activity of alpha-glucosidase, beta-glucosidase, beta-galactosidase, alpha-fucosidase, beta-xylosidase was found in heart muscle, liver, kidney and lung. Hydralazine produced a more significant increase in the enzyme activity than todralazine. The obtained results suggest drug-induced connective tissue damage, probably of an inflammatory type. The mechanism of this phenomenon and its relationship to immunological alterations remain unclear.
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PMID:Influence of long-term treatment with hydrazinophthalazines on the activity of lysosomal exoglycosidases in rat tissues. 326 91

Homogenates of Giardia lamblia trophozoites exhibited the following hydrolase activities: acid phosphatase (EC 3.1.3.2), proteinase (EC 3.1.4) with urea-denatured hemoglobin and N-benzoyl-DL-arginine-2-naphthylamide as substrates, deoxyribonuclease (EC 3.1.4.5), and ribonuclease (EC 2.7.7.16). beta-N-Acetylglucosaminidase (EC 3.2.1.30), beta-galactosidase (EC 3.2.1.23), beta-glucuronidase (EC 3.2.1.31), alpha-D-glucosidase (EC 3.2.1.20), beta-D-glucosidase (EC 3.2.1.21), and beta-D-xylosidase (EC 3.2.1.37) activities were below the level of detection. Differential and isopycnic centrifugation of homogenates demonstrated that giardial hydrolases were localized in a single-particle population sedimenting at 7200g for 30 min. The particles had a buoyant density in sucrose of 1.15 and exhibited latency. Latency was completely destroyed by Triton X-100 or 15 cycles of freezing and thawing. After centrifugation of Triton- or freeze-thaw-treated particle fractions, the hydrolase activities, though no longer latent, were still sedimentable suggesting tight binding to the organelle membrane. Latency was destroyed simultaneously for all hydrolases, in direct proportion to the amount of Triton added to a particle preparation or to the number of times a particle preparation was subjected to freezing and thawing. These results support the suggestion that the hydrolases of G. lamblia trophozoites are localized in a single-particle population of lysosome-like organelles.
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PMID:Giardia lamblia: localization of hydrolase activities in lysosome-like organelles of trophozoites. 327 50

In Creutzfeldt-Jakob disease (CJD), there are prominent ultrastructural alterations of the plasma membrane, which contains many glycolipids and glycoproteins. Glycosidases can degrade glycolipids and glycoproteins. Gangliosides, a subset of glycolipids, are decreased in amount at the terminal stages of CJD, and CJD infectivity is closely associated with membrane rich fractions. We therefore studied 10 glycosidases, and found a statistically significant increase in beta-xylosidase, beta-glucuronidase, N-acetyl-beta-D-glucosaminidase and N-acetyl-beta-D-galactosaminidase activities in CJD. In contrast, alpha-glucosidase, beta-glucosidase, alpha-galactosidase, alpha-mannosidase, alpha-fucosidase, and beta-galactosidase were not significantly changed. The above results are consistent with degenerative membrane changes observed morphologically, and with increased degradation of sugar residues on lipids and/or proteins. These changes may be effected by the accumulation of the CJD agent in cell membranes. We suggest that the higher activities of these enzymes in CJD may be partially responsible for some of the structural and biochemical alterations in CJD infected brains.
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PMID:Cerebral glycosidases in experimental Creutzfeldt-Jakob disease. 328 70


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