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

A kinetic study was done to identify the ionizable groups in the active site of Aspergillus niger alpha-glucosidase (ANGase). From dependence of V and Km values on pH, we obtained the ionization constants of essential ionizable groups 1 and 2 of free enzyme; pKe1 = 3.2 and pKe2 = 6.4. When the dielectric constant of the reaction mixture was decreased, the pKe1 and pKe2 were shifted to higher values. The ionization heats (delta H's) of ionizable groups 1 and 2 were measured to be -0.4 kcal/mol and 0 kcal/mol, respectively. The water-soluble carbodiimide (WSC), a specific reagent for carboxyl groups, inactivated the enzyme activity completely, and maltose as substrate decreased the inactivation. The WSC did not modify the free Cys. These findings suggest that the essential ionizable groups of ANGase are two kinds of carboxyl groups: one is a charged type (-COO-, ionizable group 1), and the other is a protonated type (-COOH, ionizable group 2).
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PMID:Identification of essential ionizable groups in active site of Aspergillus niger alpha-glucosidase. 909 52

Glycosyl-trehaloses with an isomaltosyl residue were synthesized by alpha-glucosidase from Aspergillus niger by using maltotetraose as a glucosyl donor and trehalose as the acceptor. The one trisaccharide and two tetrasaccharides formed were isolated by successive column chromatography. The results of an enzymatic digestion, methylation analysis, and 13C-NMR studies indicated that these oligosaccharides were alpha-isomaltosyl alpha-glucoside, alpha-isomaltotriosyl alpha-glucoside and alpha-isomaltoside. These oligosaccharides were not fermented to an acid by Streptococcus mutans, and they effectively inhibited water-insoluble glucan synthesis from sucrose by glucosyltransferase. In an in vitro utilization test with human intestinal bacteria, these oligosaccharides were predominantly utilized by Bifidobacteria.
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PMID:Synthesis by an alpha-glucosidase of glycosyl-trehaloses with an isomaltosyl residue. 914 29

Two studies were conducted to investigate whether vitamin A-deficient rats were more susceptible to intestinal injury caused by methotrexate (MTX), since vitamin A deficiency alone causes only mild changes to jejunal structure and function. Weanling male rats were fed a vitamin A-deficient diet (-VA) for 40-42 d and compared to rats either pair-fed (PF) or with free access (+VA) to the same diet. Drinking water of PF and +VA rats was supplemented with 37.5 microg (Study 1) or 75 microg (Study 2) vitamin A (Rovimix A 500W)/d. Rats in each group received MTX (-VAMTX, PFMTX, +VAMTX) or vehicle. MTX administration reduced intestinal mucosal wet weight, protein and DNA concentrations, and sucrase and maltase activities in -VA and PF rats (P < 0.02). In Study 1, -VAMTX rats developed a severe jejunal enteropathy and had a higher incidence of diarrhea (P < 0.005), greater weight loss (P < 0.005), more disruption of villus architecture (P < 0.0001) and lower disaccharidase activity (P < 0.007) than PFMTX rats. Similar results were observed in Study 2. Liver retinol concentration (but no other variable) was greater in rats receiving 75 microg vitamin A/d (P < 0.001) than in those receiving 37.5 microg/d. The interaction of vitamin A deficiency and small intestinal injury may explain the efficacy of vitamin A supplementation in preventing childhood diarrheal disease mortality in developing countries, and highlights the need for ensuring adequate vitamin A status in people worldwide with diseases and/or treatments which may injure the gastrointestinal tract.
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PMID:Vitamin A deficiency exacerbates methotrexate-induced jejunal injury in rats. 916

Among progeny of a hybrid (Rana shqiperica x R. lessonae) x R. lessonae, 14 of 22 loci form four linkage groups (LGs): (1) mitochondrial aspartate aminotransferase, carbonate dehydratase-2, esterase 4, peptidase D; (2) mannosephosphate isomerase, lactate dehydrogenase-B, sex, hexokinase-1, peptidase B; (3) albumin, fructose-biphosphatase-1, guanine deaminase; (4) mitochondrial superoxide dismutase, cytosolic malic enzyme, xanthine oxidase. Fructose-biphosphate aldolase-2 and cytosolic aspartate aminotransferase possibly form a fifth LG. Mitochondrial aconitate hydratase, alpha-glucosidase, glyceraldehyde-3-phosphate dehydrogenase, phosphogluconate dehydrogenase, and phosphoglucomutase-2 are unlinked to other loci. All testable linkages (among eight loci of LGs 1, 2, 3, and 4) are shared with eastern palearctic water frogs. Including published data, 44 protein loci can be assigned to 10 of the 13 chromosomes in Holarctic Rana. Of testable pairs among 18 protein loci, agreement between Palearctic and Nearctic Rana is complete (125 unlinked, 14 linked pairs among 14 loci of five syntenies), and Holarctic Rana and Xenopus laevis are highly concordant (125 shared nonlinkages, 13 shared linkages, three differences). Several Rana syntenies occur in mammals and fish. Many syntenies apparently have persisted for 60-140 x 10(6) years (frogs), some even for 350-400 x 10(6) years (mammals and teleosts).
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PMID:Linkage groups of protein-coding genes in western palearctic water frogs reveal extensive evolutionary conservation. 928 85

Ingestion of fermented dairy products induces changes in the equilibrium and metabolism of the intestinal microflora and may thus exert a healthful influence on the host. We compared the effects of consumption of a traditional yogurt, a milk fermented with yogurt cultures and Lactobacillus casei (YC), and a nonfermented gelled milk on the fecal microflora of healthy infants. Thirty-nine infants aged 10-18 mo were randomly assigned to one of three groups in which they received 125 g/d of one of the three products for 1 mo. The following indexes were not modified during the supplementation period or for 1 wk after the end of supplementation: total number of anaerobes, bifidobacteria, bacteroides, and enterobacteria; pH; water content; concentrations of acetate, butyrate, propionate, and lactate; and bacterial enzyme activity of beta-galactosidase and alpha-glucosidase. In contrast, in the yogurt group the number of enterococci in fecal samples increased (P < 0.05), whereas the percentage of branched-chain and long-chain fatty acids, which are markers of proteolytic fermentation, decreased (P < 0.05). In the YC group, the percentage of children with > 6 log10 colony-forming units lactobacilli/g feces increased (P < 0.05), whereas the potentially harmful enzyme activity of beta-glucuronidase and beta-glucosidase decreased (P < 0.05). These decreases were particularly marked in those infants in the YC group in whom activity of the enzymes was initially unusually high.
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PMID:Milk fermented with yogurt cultures and Lactobacillus casei compared with yogurt and gelled milk: influence on intestinal microflora in healthy infants. 944 Mar 84

1. The effect of the acute or chronic oral administration of miglitol (Bay M 1099 alpha-glucosidase inhibitor) to non-insulin-dependent diabetic rats was studied. 2. The acute oral administration of miglitol (10 mg/kg b.w.) reduced significantly the increment of blood glucose after oral maltose (2 g/kg b.w.) overload (364 +/- 58 and 205 +/- 12 mmol/90 min, without and with miglitol respectively; P < 0.05). 3. Under chronic oral administration of miglitol (10 mg/kg b.w.), two days after the start of treatment the blood glucose dropped from 7.53 +/- 9.59 to 4.40 +/- 5.50 mmol/l. The plasma insulin, cholesterol, or triglycerides levels were not modified. 4. A significant reduction (P < 0.01) in water and food intake was observed. Normal rats values were not affected by miglitol treatment.
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PMID:Effect of miglitol administration to non-insulin-dependent diabetic rats. 945 93

Partially purified hot-water extracts of the roots of plants of the Sophora family suppressed the increase in blood glucose concentration of rats in the oral sugar tolerance test. The extracts also inhibited rat intestinal sucrase and maltase. The most potent sample was about 15 times more active than catechin, a positive control, in these experiments.
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PMID:Suppression by water extracts of Sophora plants of sucrose-induced hyperglycemia in rats and inhibition of intestinal disaccharidases in vitro. 969 7

The C57BL/6 (B6) mouse is more sensitive to the effects of a high-fat diet than the A/J strain. The B6 mouse develops severe obesity, hyperglycemia, and hyperinsulinemia when fed this dietary regimen. This study was conducted to determine the effects of dietary fat and sucrose concentrations on body composition and intestinal sucrase (EC 3.2.1.48) and maltase (EC 3.2.1.20) activity in these two mouse strains. High-fat diets, regardless of sucrose content, resulted in significant weight gain, higher body fat, and lower body protein and water content in both strains of mice. The shift toward higher body fat and lower protein and water content was far greater in the B6 strain. Low-fat, high-sucrose diets resulted in lower body weight in both strains, as well as significantly greater body protein content in B6 mice. Analysis of intestinal sucrase showed that the enzyme was less active in B6 mice when the diet was high in sucrose. Both sucrase and maltase had lower activity in the presence of high dietary fat in both mouse strains. The percent reduction of intestinal enzyme activity due to dietary fat was similar in both strains. The B6 mouse exhibits disproportionate weight gain and altered body composition on a high-fat diet. This coupled with the reduced body weight and increased body protein on a low-fat, high-sucrose diet suggests that factors-relative to fat metabolism rather than sucrose metabolism are responsible for obesity.
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PMID:Differential effects of fat and sucrose on body composition in A/J and C57BL/6 mice. 982 12

The aqueous methanolic extract of an Indian natural medicine, the roots of Salacia oblonga Wall. (Celastraceae), was found to show inhibitory activity on the increase in serum glucose level in sucrose- and maltose-loaded rats. The water-soluble and ethyl acetate-soluble portions from the aqueous methanolic extract showed inhibitory activities on alpha-glucosidase and aldose reductase, respectively. From the water-soluble portion, potent alpha-glucosidase inhibitors, salacinol and kotalanol, were isolated, together with nine sugar related components, while a new friedelane-type triterpene, kotalagenin 16-acetate, was isolated from the ethyl acetate-soluble portion along with known diterpenes and triterpenes. The structure of kotalagenin 16-acetate was elucidated on the basis of physicochemical evidence. Principal components from this natural medicine were examined in terms of inhibitory activity on aldose reductase, and the diterpene and triterpene constituents, including the new kotalagenin 16-acetate, were found to be responsible components for the inhibitory activity on aldose reductase.
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PMID:Antidiabetic principles of natural medicines. IV. Aldose reductase and qlpha-glucosidase inhibitors from the roots of Salacia oblonga Wall. (Celastraceae): structure of a new friedelane-type triterpene, kotalagenin 16-acetate. 1074 16

An AOAC collaborative study was conducted to evaluate the accuracy and reliability of an enzyme assay kit procedure for measuring oligofructans and fructan polysaccharide (inulins) in mixed materials and food products. The sample is extracted with hot water, and an aliquot is treated with a mixture of sucrase (a specific sucrose-degrading enzyme), alpha-amylase, pullulanase, and maltase to hydrolyze sucrose to glucose and fructose, and starch to glucose. These reducing sugars are then reduced to sugar alcohols by treatment with alkaline borohydride solution. The solution is neutralized, and excess borohydride is removed with dilute acetic acid. The fructan is hydrolyzed to fructose and glucose using a mixture of purified exo- and endo-inulinanases (fructanase mixture). The reducing sugars produced (fructose and glucose) are measured with a spectrophotometer after reaction with para-hydroxybenzoic acid hydrazide. The samples analyzed included pure fructan, chocolate, low-fat spread, milk powder, vitamin tablets, onion powder, Jerusalem artichoke flour, wheat stalks, and a sucrose/cellulose control flour. Repeatability relative standard deviations ranged from 2.3 to 7.3%; reproducibility relative standard deviations ranged from 5.0 to 10.8%.
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PMID:Measurement of total fructan in foods by enzymatic/spectrophotometric method: collaborative study. 1077 73


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