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)

The effects of salts and non-ionic detergents on renal brush borders have been studied. 2 M sodium chloride, iodide or thiocyanate dissociated up to 40% of the protein from the brush borders, destroying the core filaments and resulting in the formation of membrane vesicles; EDTA had a similar effect on structure but released little protein. Triton X-100 and Nonidet P-40 extracted up to 60% of the protein including the major membrane glycoproteins and the enzymes trehalase, maltase and aminopeptidase (microsomal). Triton exhibited a selective effect on lipids removing phosphatidylserine, phosphatidylethanolamine and sphingomyelin but not the bulk of the phosphatidylcholine or cholesterol. The residual structures after Triton extraction comprised the core filaments associated with vesicles of lipid containing alkaline phosphatase and several other proteins. Treatment of these core-vesicle complexes with 2 M sodium chloride dissociated the filaments, releasing the vesicles which could be recovered as a pellicle on centrifugation. It is suggested that the proteins found in the vesicles might serve to interconnect the core filaments with the lipid bilayer.
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PMID:Studies on the structure of the rabbit kidney brush border. 11 89

Normal reference values of lysosomal enzyme activities (alpha-glucosidase, mannosidase, fucosidase and arylsulfatase-A) were determined in chorionic villi obtained from artificial abortion in the first trimester of normal pregnancies (gestational weeks 6 to 11). Villi were homogenized comparatively either in saline or in Triton X-100 detergent. The alpha-glucosidase, mannosidase and arylsulfatase-A enzyme activities significantly diminished if homogenization was done in saline instead of Triton-X while the difference in fucosidase activity was not significant. Significant correlation was detected between alpha-glucosidase activity and week of gestation. It is suggested that Triton X-100-homogenization should be used for the lysosomal enzyme determinations in chorionic villi because the solubilization of enzymes from the lysosomes is complete in this case than with homogenization in saline.
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PMID:Lysosomal enzyme activities in frozen, non-cultured chorionic villi for prenatal diagnosis of enzymopathies. 136 80

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

An enzyme has been found in Triton-treated rat liver Golgi membranes which trims Glc1Man9GlcNAc to Man8GlcNAc with the release of Glc alpha 1-3Man. By removing a glucosylmannose disaccharide and yielding only one Man8GlcNAc isomer, this endo-alpha-D-mannosidase provides a processing route alternative to the sequential actions of alpha-glucosidase II and alpha-mannosidase I. The endomannosidase was fully active in the presence of 1-deoxynojirimycin and EDTA which inhibited exoglycosidase release of glucose and mannose, respectively, and these agents were, therefore, included in the standard assay. The specific activity of the endomannosidase was found to be 69-fold greater in Golgi than in rough endoplasmic reticulum (RER) membranes, and Golgi-RER mixing experiments excluded the possibility that the low activity in the RER was the result of some inhibitor present in this fraction. The neutral pH optimum (approximately 7.0) of the enzyme was consistent with a role in N-linked oligosaccharide processing. The existence of an endo-alpha-D-mannosidase pathway for glucose removal could provide an explanation for the incomplete block in oligosaccharide processing which is observed in cells with inhibited or deficient alpha-glucosidase.
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PMID:Golgi endo-alpha-D-mannosidase from rat liver, a novel N-linked carbohydrate unit processing enzyme. 381 65

Leukocytes were obtained from 14 healthy subjects, one patient with the infantile form, two patients with the adult variant of acid maltase deficiency, two patients with chronic myelocytic leukemia, two patients with acute myeloid leukemia, and two patients with chronic lymphotic leukemia. In addition, lymphocytes were prepared from three normal subjects, and five established lymphoid lines were used. Cells were extracted either with Triton 0, 2%, or with water followed by 0.2% Triton. alpha-Glucosidase activity was measured in water homogenates, water extracts after centrifugation, and Triton extracts, with or without antisera directed against acid maltase (EC 3.2.1.3) and renal maltase (EC 3.2.1.20). The percentage of acid and renal maltases was then calculated in each soluble fraction. Normal whole leukocytes (mostly granulocytes) contain both acid and "renal" maltases, whereas normal lymphocytes contain very little or no "renal maltase." This isozyme is present in chronic myelocytic leukemia, but is absent in acute myeloid and chronic lymphocytic leukemia as well as in established lymphoid lines. Acid maltase is almost completely extracted with water, whereas renal maltase is extracted only with Triton. From the results, it appears that for the diagnosis of alpha glucosidase deficiency, cells should be extracted in water and centrifuged before determination. Lymphocytes, which are devoid of renal maltase, are a better diagnostic material than are granulocytes.
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PMID:White blood cells and the diagnosis of alpha-glucosidase deficiency. 676 91

Maltase/glucoamylase from the rat intestinal brush-border membrane was solubilized by homogenization of the intestinal mucosa in buffer containing 0.5% Triton X-100. After removal of the detergent with butan-1-ol, the enzyme was purified by chromatography on Sepharose 4B and DEAE-cellulose. The final specific activity was 70.3 units/mg of protein in six preparations, comparing favourably with the specific activity of 65.0 units/mg of protein of a pure papain-solubilized maltase/glucoamylase previously isolated and characterized by us [Flanagan & Forstner (1978) Biochem. J.173, 553-563]. The two enzymes were compared. Both migrated as single bands with the same mobility on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, were eluted at the same volume from Sepharose 4B, and had the same sedimentation pattern in mannitol gradients. The amino acid composition was similar; content of total apolar residues differed by 1.0mol%. Antibodies prepared against either enzyme gave identical precipitin lines with each. Neither enzyme bound tritiated Triton X-100. The only difference noted was the tendency of the detergent-solubilized enzyme to aggregate on storage, whereas the papain-solubilized enzyme remained unchanged. Both enzymes had two N-termini, glycine and arginine. When the two enzymes were dissociated by boiling in sodium dodecyl sulphate, each exhibited the same five species on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. Single N-termini were found in the two smaller species, 1 (glycine) and 2 (arginine), whereas larger species (3-5) had both N-terminal amino acids. Both the Triton- and papain-solubilized enzymes appear to be oligomers of species 1 and 2, indicating that the native enzyme contains two subunit types. Aggregation in aqueous solutions does not depend on a proteolytically susceptible peptide fragment at the N-terminus of either subunit.
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PMID:Isolation of a detergent-solubilized maltase/glucoamylase from rat intestine and its comparison with a maltase/glucoamylase solubilized by papain. 677 61

Inhibition of carbohydrate digestion by the alpha-glucosidase inhibitor acarbose (BAY g 5421)reduces carbohydrate-induced postprandial blood glucose increase and insulin secretion. As a consequence, in feeding experiments sucrose-induced hyperinsulinemia and hypertriglyceridemia in genetically obese (fa,fa) "Zucker" rats were dose-dependently reduced by addition of acarbose to the diet (15-80 mg/100 g feed). The body weight gain was dose-dependently reduced. In short-term experiments with a fat-free diet acarbose not only prevented serum triglyceride and free fatty acid increase in spite of lowered insulin concentrations but also decreased their concentrations below the values obtained on standard feed. Under these conditions there were no significant effects on body weight. Hypertriglyceridemia induced by i.v. injection of the lipoprotein lipase inhibitor Triton WR 1339 was reduced without affecting body weight in "Zucker" rats after 3 days on a fat-free diet supplemented with acarbose. The triglyceride increase was even lower than in animals kept on standard feed. The data demonstrate that acarbose reduces sucrose-induced hypertriglyceridemia in (fa,fa) "Zucker" rats by diminishing VLDL production and/or secretion rather than by increasing VLDL removal from the blood.
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PMID:Reduction of carbohydrate-induced hypertriglyceridemia in (fa,fa) "Zucker" rats by the alpha-glucosidase inhibitor acarbose (BAY g 5421). 704 75

The activities of acid beta-glucuronidase, alpha-mannosidase, alpha-glucosidase, alpha-galactosidase, beta-galactosidase and beta-N-acetylglucosaminidase were analysed in seminal plasma and spermatozoa from 26 infertile men with varicocele and from 36 men of normal fertility. Semen samples from ten men with non-obstructive azoospermia were used as control specimens that contained the other components of semen. Spermatozoa were solubilized by both physical (homogenization) and chemical (Triton-X100) methods to obtain the soluble and non-soluble fractions. The activities of several glycosidases measured both in seminal plasma and spermatozoa were directly correlated with the numbers of spermatozoa and sperm motility, confirming previous studies. As some infertile patients with varicocele have normal semen parameters, whereas others have low numbers of spermatozoa and low sperm motility, the varicocele patients were prospectively divided into two groups: one (n = 15) with normal spermiograms and the other (n = 11) with abnormal spermiograms. The activities (expressed in mU ml(-1)) of alpha-mannosidase, beta-galactosidase and beta-N-acetylglucosaminidase in seminal plasma of normozoospermic infertile patients with varicocele were significantly higher than those of fertile controls, but not when expressed in U per 10(8) spermatozoa. The activities of beta-glucuronidase, alpha-mannosidase, beta-galactosidase and beta-N-acetylglucosaminidase in seminal plasma when expressed in U per 10(8) spermatozoa in varicocele patients with abnormal spermiograms were significantly higher than in those of men of normal fertility. The activity of alpha-mannosidase in the soluble fraction of sperm homogenates, expressed as U per 10(8) spermatozoa, was significantly higher in infertile patients with varicocele and abnormal spermiograms than in controls. In the non-soluble fraction of spermatozoa from infertile patients with varicocele, there was an increase in the expression of beta-galactosidase and beta-N-acetylglucosaminidase activities compared with the fraction of spermatozoa from fertile subjects. In summary, infertile patients with varicocele displayed an overexpression of acid alpha-mannosidase, beta-galactosidase and beta-N-acetylglucosaminidase activities in seminal plasma and spermatozoa that may be associated with functional defects in spermatozoa as these glycosidases play an important role in mammalian fertilization.
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PMID:Abnormal expression of acid glycosidases in seminal plasma and spermatozoa from infertile men with varicocele. 1188 18

Hydroxytyrosol (HT) is a natural polyphenol antioxidant that exists in olive oil. In the study of multifunctional hypolipidemic of nicotinic derivatives, we found that hydroxytyrosol nicotinate (HT-N) incorporation of niacin with HT displayed ?-glucosidase inhibitory activities in vitro, such as yeast ?-glucosidase (IC50?=?117.72??M) and rat intestinal ?-glucosidases maltase (IC50?=?31.86??M) and sucrase (IC50?=?22.99??M), and had a good control of postprandial blood glucose (PBG). HT-N shown significantly hypoglycemic action by 16.9% and protection of pancreatic tissue in type 2 diabetic mellitus (T2DM) mouse model. HT-N also shown a potent antioxidant activity and property of anti-glycation in vitro, which were benefit for ameliorating diabetic complications. Moreover, HT-N exhibited much significant hypolipidemia, lowering plasma triglyceride (TG), total cholesterol (TC), and malonaldehyde (MDA) by 34.6%, 45.8% and 32.1% respectively, in hyperlipidemic mice induced by Triton WR 1339. The results indicated that HT-N has hypolipidemic, hypoglycemic and antioxidant actions. All these properties could be conducive to amelioration of oxidative stress, hyperlipidemia, and diabetes that HT-N may serve as a multifunctional potential therapeutic strategy in diabetic patients with hyperlipidemia.
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PMID:Hydroxytyrosol nicotinate, a new multifunctional hypolipidemic and hypoglycemic agent. 2971 Apr 69