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)

Recent studies have demonstrated that the human intestinal enzymes of carbohydrate digestion and metabolism can be regulated by dietary sugars. These studies have utilized direct assay of intestinal mucosal enzyme activity. Mucosa has been obtained by the use of peroral jejunal biopsy techniques which provide 10-15 mg of mucosa in a safe, simple and reproducible manner. Dietary sucrose, as compared to dietary glucose, increases the activities of the jejunal disaccharidases, sucrase and maltase, but not lactase. Fructose reproduces the sucrose effect and appears to be the active principle in the sucrose molecule. Lactose deprivation or lactose feeding does not alter lactase activity. Fructose has been useful in treating one patient with sucrase-isomaltase deficiency. Jejunal glycolytic enzyme activities are also regulated by dietary sugars. Certain enzymes are highest with specific dietary carbohydrates, lower with other sugars and lowest on a carbohydrate-free diet. The regulation of human jejunal glycolytic enzyme activity takes place in hours, whereas the change in disaccharidase activity occurs in 2-5 days. The mechanism of this regulation is not known. Additional investigations have shown that jejunal glycolytic enzyme activities but not the disaccharidases are controlled by oral folic acid as well. This effect occurs within 1 day also. The mechanism is unknown. Large doses of folate have been of benefit in a few patients with certain glycolytic enzyme deficiency states. Preliminary studies have demonstrated that selected patients with chronic undiagnosed intestinal disorders fail to manifest an adaptive response of their jejunal glycolytic enzyme activities to dietary sugars. This condition has been termed a "maladaptation syndrome.".
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PMID:Diet and intestinal enzyme adaptation: implications for gastrointestinal disorders. 16 4

Yeast strains bearing a deficiency in trehalose-6-phosphate synthase activity are unable to accumulate trehalose on any carbon source unless they contain one of the MAL genes. If the gene is inducible then synthesis of trehalose occurs specifically during growth on maltose: when the MAL gene is constitutive then trehalose accumulation can also be seen when cells are grown on glucose. Different systems for trehalose synthesis were suggested: one of them would require the UDPG-linked trehalose synthase whereas the second would utilize an alternative pathway. We proposed a mechanism by which the gene-product of a MAL gene would serve as a common positive regulator for the expression of the genes coding for maltose permease, alpha-glucosidase and some component of the trehalose accumulation system. In order to elucidate this novel pathway a strain lacking UDPG-linked trehalose synthase activity and harboring a defect in maltose uptake was constructed. Excessive maltose uptake resulted in accumulation of intracellular maltose, and twice as much trehalose as in a control strain. Partial inhibition of hexokinase by xylose affected the ratio between internal maltose and trehalose and significantly reduced glycogen synthesis. Sodium fluoride also blocked glycogen synthesis but allowed for trehalose accumulation. Moreover, a mutant which lacks hexokinase I and II was unable to accumulate trehalose when grown on glucose in spite of the presence of a constitutive MAL2 gene. These results suggest that trehalose synthesis would require G-6-P formation derived from maltose. Such a deviation would allow for slowing down the glycolytic flux which, in turn, would favour efficient maltose utilization.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Further evidence for the alternative pathway of trehalose synthesis linked to maltose utilization in Saccharomyces. 344 33

The effect of oral folic acid on jejunal glycolytic enzyme activity in five fasting obese patients and in three normal male volunteers on a constant 3000 cal diet was studied. The glycolytic enzymes, fructokinase, hexokinase, glucokinase, fructose-1-phosphate aldolase, and fructose diphosphate aldolase, and the disaccharidases, sucrase, maltase, and lactase were measured. In both the fasting patients and the normal volunteers, oral folic acid significantly increased the jejunal glycolytic enzyme activities but had no effect on disaccharidase activity. When oral folic acid was discontinued in the normal volunteers, the glycolytic enzyme activities returned to control values. In the obese patients, refeeding and folic acid caused a further increase in glycolytic enzyme activities above that seen with fasting and folic acid. In contrast to oral folic acid, intramuscular folic acid, oral vitamin B(12), and oral tetracycline had no effect on glycolytic enzyme activities. These studies demonstrate that oral folic acid which is neither a substrate nor a coenzyme of these enzymes, increases human jejunal glycolytic enzyme activity in a specific fashion. This would appear to be an action of oral folic acid which has not been recognized previously.
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PMID:Regulation of human jejunal glycolytic enzymes by oral folic acid. 582 69

The previously isolated recessive mutant allele hex2-3 of Saccharomyces cerevisiae caused a defect in carbon catabolite repression of maltase, invertase, malate dehydrogenase, and respiration but at the same time led to an extreme sensitivity to maltose (Zimmerman and Scheel, 1977; Entian and Zimmermann, 1980). Addition of maltose to a growing culture of a hex2-3 mutant resulted within 60 to 90 min in an inhibition of growth, glycolysis, and de novo protein synthesis. This was not accompanied by any abnormal levels of glycolysis metabolites or glycolytic enzyme activities. However, inhibitory effects coincided with a dramatic increase in intracellular glucose up to 150 mM relative to cell water as opposed to 2.5 mM in wild-type cells. This abnormal behavior is interpreted as a result of an uncontrolled maltose uptake in hex2 mutants, which in combination with increasing maltase activity results in an accumulation of intracellular glucose. Obviously the amount of available glucose surpassed glycolytic capacity in hex2 mutants. Properties of mutant alleles hex2 and hex1 (see Entian and Zimmermann, 1980) clearly show, that specific gene functions are involved in adapting the rate of sugar uptake into the cell to the actual glycolytic capacity.
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PMID:A defect in carbon catabolite repression associated with uncontrollable and excessive maltose uptake. 700 23

Enzymatic activity was measured on two beaches of the Ligurian Sea (NW Mediterranean) during late spring and summer 2003. The detected activities (leucine aminopeptidase, beta-glucosidase, alpha-glucosidase, and beta-N-acetylglucosaminidase) were related to the available organic substrates (proteins and carbohydrates) and to the bacterial community (expressed in terms of abundance, biomass, and frequency of cell division). The very low chlorophyll a concentrations (never higher than 40 ng g(-1)) suggested that heterotrophic microorganisms play a major role in the beach ecosystem. Enzymatic activities devoted to organic matter degradation were lower in the emerged part of the beaches and higher in the sites covered, permanently or temporarily, by seawater, suggesting that sea action enlivens the degradation processes. Leucine aminopeptidase ranged from 0.26 to 13.02 nmol g(-1)h(-1), and beta-glucosidase (the most expressed glycolytic enzyme) from 0.03 to 4.51 nmol g(-1)h(-1). Strong changes in the proteolytic/glycolytic activity ratio were observed, with a sudden rise in glycolysis during summer, leading to ratio values from about 30 down to 1. Thus, beaches were identified as preferential degradation sites, where very refractory compounds such as cellulose may also be efficiently processed.
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PMID:Enzymatic activity on sandy beaches of the Ligurian Sea (NW Mediterranean). 1605 75