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)

Genetic analysis of the MAL6 locus has previously yielded mal6 mutants which fall into a single complementation group and which are noninducible for maltase and maltose permease. However, the strains used in these studies contained additional partially functional copies of MAL1 (referred to as MAL1g) and MAL3 (referred to as MAL3g). Using a strain lacking MALg genes, we have isolated two classes of mutants and these classes correspond to mutations in MAL63 and MAL61, two genes of the MAL6 complex. Disruptions of MAL63 are noninducible for maltase and maltose permease and for their corresponding mRNAs. The mal6 mutants are shown to map to MAL63. Inducer exclusion as a cause of the noninducible phenotype of the mal63 mutations has been eliminated by constructing a mal63 mutant in a strain constitutive for maltose permease; the strain remains noninducible. These results rigorously demonstrate that MAL63 is a regulatory gene which plays a positive role in the regulation of maltose fermentation.
Curr Genet 1988 Sep
PMID:MAL63 codes for a positive regulator of maltose fermentation in Saccharomyces cerevisiae. 305 30

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.
Carbohydr Res 1986 Sep 15
PMID:Synthesis of 1,4-dideoxy-1,4-imino-D-glucitol, a glucosidase inhibitor. 309 67

In the present study, the protective effect of PGE2 on intestinal damage in indomethacin-treated adult rats was investigated. Ileal integrity was evaluated making use of different biochemical and histological parameters: activities of sucrase, maltase and diamine oxidase; concentrations of DNA, putrescine, spermidine and spermine; incorporation of 3H-thymidine into DNA; mitotic index and mucosal thickness. Results expressed per g of mucosal weight, showed that: maltase and diamine oxidase activities as well as DNA, spermidine and spermine concentrations decreased markedly in indomethacin-treated rats when compared to control rats; the decrease of maltase activity as well as DNA, spermidine and spermine concentration was less pronounced in PGE2-treated rats when compared to indomethacin-treated rats; 3H-thymidine incorporation into DNA and mitotic index values showed no significant variation in the course of different treatments; mucosal thickness increased strongly, in PGE2-protected rats. We suggest that PGE2 could protect the rat's intestinal mucosa against the effects of indomethacin through a trophic action on intestinal villi.
Life Sci 1987 Sep 07
PMID:Effect of prostaglandin E2 on the small intestine of indomethacin-treated rats. 311 78

All 18 2-year-old Brahman bulls grazing in a paddock containing Castanospermum australe trees were diagnosed as heterozygotes for Pompe's disease by measurement of mononuclear cell alpha-glucosidase activity. However, removal of the bulls to a paddock free of C. australe and retesting 2 months later indicated that 15 were homozygous normal. An in vitro assay demonstrated that a crude aqueous extract of seeds from these C. australe trees contained a potent inhibitor of mononuclear cell alpha-glucosidase. Two Hereford steers were dosed with 0.6 g C. australe seed/kg bodyweight for 6 days. The alpha-glucosidase activity in blood mononuclear cells declined to 5% of normal within 48 h of commencement of dosing. It was therefore assumed that the bulls had consumed C. australe seeds. A means of differentiating true heterozygotes from animals consuming the toxic seed, using the ratio of plasma alpha-glucosidase activity at pH 5.6 to that at pH 3.7, is proposed.
Aust Vet J 1987 Sep
PMID:Inhibition of bovine alpha-glucosidase by Castanospermum australe and its effect on the biochemical identification of heterozygotes for generalised glycogenosis type II (Pompe's disease) in cattle. 312 15

The plant alkaloids castanospermine, dihydroxymethyldihydroxypyrrolidine and deoxynojirimycin have recently been shown to have potential anti-HIV activity [(1987) Proc. Natl. Acad. Sci. USA 84, 8120-8124; (1987) Nature 330, 74-77; (1987) Lancet i, 1025-1026]. They are thought to act by inhibiting alpha-glucosidase I, an enzyme involved in the processing of N-linked oligosaccharides on glycoproteins. We report here the relative efficacy of a spectrum of amino-sugar derivatives as inhibition of HIV cytopathicity. Several alpha-glucosidase inhibitors and alpha-fucosidase inhibitors were found to be active at concentrations which were non-cytotoxic.
FEBS Lett 1988 Sep 12
PMID:Inhibition of HIV replication by amino-sugar derivatives. 316 33

The present study aimed at investigating the metabolic effects and tolerance of two desoxynojirimycin derivatives with alpha-glucosidase inhibitory properties (BAY m 1099 and BAY o 1248). The study was performed in a double-blind cross-over manner on 7 insulin-treated outpatient diabetics (6 males, 1 female; mean age 43 +/- 14 years; mean duration of diabetes 5.8 +/- 4.2 years; all within +/- 10% of their ideal body weight). The usual diet containing 24.5 +/- 8 g dietary fibers and 52 +/- 22 g simple sugars was maintained throughout the study. After a 7-day run-in period, 4 consecutive periods of 7 days were considered for each patient. The patients were randomly allocated for 1 week to BAY o 1248 (20 mg with breakfast) or Bay m 1099 (50 mg with breakfast and dinner). After a 7-day wash-out period the patients underwent the alternate treatment. At the end of each period, the patients were admitted to the Metabolic Ward for detailed metabolic and hormonal investigations. No significant changes were observed in the daily insulin requirements (45 +/- 15 U/day). HbA1c did not change significantly. Residual insulin secretion was low (plasma C-peptide: 0.077 +/- 0.09 and 0.154 +/- 0.15 pmol/ml during fasting and 2 hours post-breakfast, respectively); it was not modified by the treatments. Increments in blood glucose were significantly lower after breakfast with both drugs. No differences were observed in plasma free insulin. A marked increase in breath hydrogen was observed after lunch with BAY o 1248 only. Clinical and biological tolerance was excellent for both compounds.(ABSTRACT TRUNCATED AT 250 WORDS)
Int J Clin Pharmacol Ther Toxicol 1987 Sep
PMID:Assessment of the clinical efficacy and tolerance of two new alpha-glucosidase inhibitors in insulin-treated diabetics. 331 59

The role of hexokinase PII in mediating carbon catabolite derepression in yeast has been examined. Hexokinase isoenzyme PII (EC 2.7.1.1) was partially degraded when protease inhibitors were omitted from the buffer used for preparation of cell-free extracts. The hexokinase PII inactivation induced by D-xylose was correlated with derepression of maltase (EC 3.2.1.20) in the wild-type strain Saccharomyces cerevisiae G-517 and in D.308.3, a strain that contains the cloned hexokinase PII gene on a multicopy plasmid. This inactivation was not correlated with the loss of hexokinase PII protein as assayed by immunoblotting. We conclude that during the derepression process there is no release of proteolytic peptides from hexokinase PII.
J Gen Microbiol 1987 Sep
PMID:Proteolysis of hexokinase PII is not the triggering signal of carbon catabolite derepression in Saccharomyces cerevisiae. 332 14

NMRI mice immunosuppressed with dexamethasone followed by challenge intraesophageally with axenic Giardia lamblia (Portland I) trophozoites had severe infection in terms of the trophozoite counts in the jejunum. Although the immunosuppressive treatment with cortisone itself resulted in a deleterious effect on brush border membrane enzymes, the decline in disaccharidases (sucrase, maltase, and lactase) and alkaline phosphatase was highly significant (P less than 0.001) following G. lamblia infection. The alterations in enzymatic activity in immune intact but infected animals demonstrated the potential of the parasite itself to cause damage to the brush border membrane. We believe that individuals with underlying immunodeficiency, upon infection with G. lamblia, may have increased damage of the brush border membrane, leading to severe malabsorption.
Dig Dis Sci 1988 Sep
PMID:Giardia lamblia infection in immunosuppressed animals causes severe alterations to brush border membrane enzymes. 276 19

An asialoglycoprotein receptor was isolated from murine liver and purified more than 1600-fold using 2-fold affinity chromatography on asialoorosomucoid-Sepharose. The purified receptor did not interact with 125I-orosomucoid, but bound to 125I-asialoorosomucoid. The binding of the receptor to asialoorosomucoid was saturable. The dissociation constant of the receptor-asialoorosomucoid complex was 0.4 X 10(-9) M. The molecular mass of the receptor, as determined with the use of specific antibodies by the immunoblotting method, was 43 kDa. High concentrations of unlabeled asialoorosomucoid and of n-aminophenyl-beta-D-galactosyl derivatives of bovine serum albumin, ovalbumin and acid alpha-glucosidase from human liver inhibited the binding of the receptor to 125I-asialoorosomucoid almost completely. The binding of the receptor to 125I-galactolyzed alpha-glucosidase was pH-dependent, with the pH optimum at 8.0-9.0. It was shown that, as in the case of 125I-asialoorosomucoid, the binding of the 125I-galactosyl derivative of alpha-glucosidase occurred in the presence of Ca2+ and was inhibited by N-acetylgalactosamine. Glycoproteins containing galactose as a terminal residue inhibited the interaction of the receptor with 125I-galactolyzed alpha-glucosidase. The possibility of directed transport of the galactolyzed alpha-glucosidase derivative into parenchymous liver cells using receptor-mediated endocytosis is discussed.
Biochim Biophys Acta 1986 Sep 04
PMID:Interaction of hepatic asialoglycoprotein receptor with asialoorosomucoid and galactolyzed lysosomal alpha-glucosidase. 352 76

The NH2-terminal sequence (25 residues) of amphiphilic single polypeptide chain maltase-glucoamylase (EC 3.2.1.20) was determined by gas-phase sequencing. The result indicates that the NH2-terminal segment anchors the enzyme to the microvillar membrane. The single-chain form and the proteolytically processed two-chain form have two distinct active sites differing in heat stability. However, both sites are sensitive to chonduritol B-epoxide and have similar substrate specificity. The amphiphilic single-chain maltase-glucoamylase and the amphiphilic proteolytically processed form were inserted into liposomes and studied by electron microscopy. The results showed that the enzyme is predominantly present as a homodimeric complex in the membrane.
J Biol Chem 1986 Sep 15
PMID:Pig intestinal microvillar maltase-glucoamylase. Structure and membrane insertion. 352 55


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