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)

Clostridium thermosulfurogenes displayed faster growth on either glucose, maltose, or starch than Clostridium thermohydrosulfuricum. Both species grew faster on glucose than on starch or maltose. The fermentation end product ratios were altered based on higher ethanol and lactate yields on starch than on glucose. In C. thermohydrosulfuricum, glucoamylase, pullulanase, and maltase were mainly responsible for conversion of starch and maltose into glucose, which was accumulated by a putative glucose permease. In C. thermosulfurogenes, beta-amylase was primarily responsible for degradation of starch to maltose, which was accumulated by a putative maltose permease and then hydrolyzed by glucoamylase. Regardless of the growth substrate, the rates of glucose, maltose, and starch transformation were higher in C. thermosulfurogenes than in C. thermohydrosulfuricum. Both species had a functional Embden-Meyerhof glycolytic pathway and displayed the following catabolic activities: ferredoxin-linked pyruvate dehydrogenase, acetate kinase, NAD(P)-ethanol dehydrogenase, NAD(P)-ferredoxin oxidoreductase, hydrogenase, and fructose-1,6-diphosphate-activated lactate dehydrogenase. Ferredoxin-NAD reductase activity was higher in C. thermohydrosulfuricum than NADH-ferredoxin oxidase activity, but the former activity was not detectable in C. thermosulfurogenes. Both NAD- and NADP-linked ethanol dehydrogenases were unidirectional in C. thermosulfurogenes but reversible in C. thermohydrosulfuricum. The ratio of hydrogen-producing hydrogenase to hydrogen-consuming hydrogenase was higher in C. thermosulfurogenes. Two biochemical models are proposed to explain the differential saccharide metabolism on the basis of species enzyme differences in relation to specific growth substrates.
 ...
PMID:Differential amylosaccharide metabolism of Clostridium thermosulfurogenes and Clostridium thermohydrosulfuricum. 393 39

The definition of "insufficient" small bowel lactase activity varies greatly among authors. The present study is aimed at redefining lactase insufficiency by comparing intestinal lactase activity and results of the lactose breath hydrogen test. Primary "insufficient" lactase activity was considered to be present when a child with a normal small bowel histology showed lactose malabsorption as measured by the lactose breath hydrogen test. The lactase activity of 22 "normal" children ranged from 0.77 to 4.57 U/g wet weight, while five children showed primary lactase insufficiency as defined above. Small bowel lactase activity in the latter patients was less than 0.74 U/g wet weight. Sucrase and maltase activities were similar in both groups of patients. We conclude that children with a normal small bowel histology should be considered to have primary lactase insufficiency when small bowel lactase activity is below 0.75 U/g wet weight.
 ...
PMID:Lactase insufficiency revisited. 393 58

An alpha-glucosidase maximally active at acid pH has been purified from human heart some 2,600-fold and its properties compared to a purified alpha-glucosidase from human liver. Molecular weight was evaluated using three different analytical procedures. The effect of various cations was determined. Thermal lability was evaluated using three different substrates. Affinity and hydrolysis velocity constants for maltose, glycogen and 4-methylumbelliferyl-alpha-D-glucose were determined for both preparations at optimal hydrogen ion concentration. Inhibition studies were carried out using the disaccharide turanose. From this study, we conclude there are no significant differences in molecular weight or kinetic properties between the cardiac and hepatic alpha-glucosidase enzymes.
 ...
PMID:Acid alpha-glucosidase from human heart. 634 72

Acarbose, an alpha-glucosidase inhibitor, lowers the glycemic excursion following the ingestion of carbohydrates, in particular, sucrose. This was confirmed with increasing doses of acarbose (0, 50, and 100 mg) and the causes investigated. The absorption of the glucose moiety of sucrose was determined from plasma tracer concentrations when overnight-fasted normal subjects received a 100-g oral sucrose load labeled with sucrose [(1-14C]glucose and a simultaneous intravenous infusion of [3-3H]glucose. As the dose of acarbose given with the sucrose load was increased from 0 to 100 mg, the percentage of the load appearing in the peripheral circulation decreased from 90% to 62%. Malabsorption was confirmed by the appearance of breath hydrogen. Simultaneously, absorption time increased from 243 to 411 min. Maximal glycemic excursions were therefore lowered from 64 to 31 mg/dl. The plasma concentrations of gastric inhibitory polypeptide and insulin decreased with the acarbose dose so that the fractional disappearance rate of glucose also decreased. However, the concentrations of glucagon-like immunoreactivity (GLI) rose, confirming the ileal appearance of malabsorbed sucrose.
 ...
PMID:The effects of an alpha-glucoside hydrolase inhibitor on glycemia and the absorption of sucrose in man determined using a tracer method. 636 57

We have tested the effectiveness of a commercial starch blocker on the digestion and absorption of dietary carbohydrates in six normal, healthy volunteers. The effectiveness of the starch blocker to attenuate or block the digestion of carbohydrate was assessed against a placebo by the measurement of end tidal breath hydrogen, plasma glucose, and insulin responses to a constant test meal. There were no significant differences in breath hydrogen, or plasma glucose and insulin responses. In vitro enzyme inhibition studies assessed the ability of the brush border enzyme maltase/glucoamylase to degrade starch in the presence of the starch blockers. A highly purified solution of rat and human maltase/glucoamylase was capable of degrading a starch solution, while 40 mM Tris-HCl (a known maltase/glucoamylase inhibitor) completely abolished the enzyme activity. These data challenge the claims that starch blocker preparations are effective in reducing or attenuating the absorption of carbohydrates or calories from a mixed meal. The ineffectiveness in vivo could be explained, in part, by the ability of the brush border enzyme maltase/glucoamylase to hydrolyze starch in the presence of starch blockers.
 ...
PMID:Effects of a commercial starch blocker preparation on carbohydrate digestion and absorption: in vivo and in vitro studies. 641 83

Acarbose (Bay g 5421) is a powerful alpha-glucoside hydrolase inhibitor of potential value in the treatment of diabetes and hypoglycemic dumping syndrome after gastric surgery. The extent of its use may be limited by symptoms produced by carbohydrate malabsorption. To minimize these, the action of low doses of acarbose on 24-h blood glucose profiles and hydrogen evolution have been studied on four ambulant volunteers on control diets, after exclusion of sucrose and also after addition of guar in an attempt to enhance the therapeutic effect. Replacement of dietary sucrose by starch abolished significant hydrogen evolution in the morning after low doses of acarbose but did not reduce its effectiveness in decreasing the mean three-meal blood glucose area by 41% (P less than 0.002). Addition of hydrated guar to this diet reduced the mean three-meal glucose area after acarbose further by 72% (P less than 0.001) but increased hydrogen evolution. The results suggest that acarbose will be both effective and acceptable given at low dose when the dietary carbohydrate is starch.
 ...
PMID:Effect of acarbose on the 24-hour blood glucose profile and pattern of carbohydrate absorption. 692 27

Fifty-gram carbohydrate tolerance tests were performed on healthy volunteers to test the activity and specificity of an alpha-glucoside hydrolase inhibitor, acarbose (BAY g 5421). Two hundred milligrams acarbose reduced the area under the blood glucose response curve by 89% (P less than 0.001) after sucrose by 80% (P less than 0.002) after starch, by 19% (N.S.) after maltose, with no effect on glucose. Breath hydrogen measurements indicated an almost complete malabsorption of the sucrose. At 50 mg acarbose, some reduction in blood glucose and insulin response to sucrose was still seen, but no significant hydrogen production. It is suggested that at lower doses, acarbose may prolong the time course over which carbohydrate is absorbed as does dietary fiber; as with fiber, it may be a useful adjunct to diabetic therapy.
 ...
PMID:Scope and specificity of acarbose in slowing carbohydrate absorption in man. 702 48

The influence of metronidazole on the breath hydrogen response and symptoms of sucrose malabsorption was investigated in a double-blind, randomized and controlled study. Carbohydrate malabsorption was induced by the competitive alpha-glucosidase inhibitor, acarbose. Metronidazole reduced flatulence and the breath hydrogen response during sucrose malabsorption without a change in intestinal carbohydrate absorption, as indicated by serum levels of gastric inhibitory polypeptide, serum insulin and blood glucose. The effect of metronidazole suggests that anaerobic bacteria mediate both signs and symptoms of the colonic response to sucrose malabsorption. In contrast to previous reports on lactose malabsorption, it was not possible to quantify sucrose malabsorption by comparing the breath hydrogen response to sucrose malabsorption with the H2 response to a lactulose load.
 ...
PMID:Influence of metronidazole on the breath hydrogen response and symptoms in acarbose-induced malabsorption of sucrose. 716 May 49

The present study was designed to determine the possible significance of a therapeutic dose (0.2 mg) of AO-128 on carbohydrate absorption by measuring the breath hydrogen concentration, which is an index of the amount of unabsorbed carbohydrate in the large intestine. Post-prandial hyperglycemia is common among diabetic patients. AO-128, a potent alpha-glucosidase inhibitor, suppressed post-prandial hyperglycemia and hyperinsulinemia in healthy volunteers at a dose of 0.2 mg with each meal. These volunteers increased the breath hydrogen concentration in response to ingestion of non-absorbable lactulose, but decreased only slightly its concentration from the basal level after sucrose ingestion, indicating complete absorption. When AO-128 (0.2 mg) was given with sucrose, hydrogen production increased only slightly compared with placebo, suggesting that the inhibitory effect of AO-128 on sucrose absorption was minimal. Only 5 g of the 100 g of sucrose was not absorbed and this 5% reduction is too small to explain the observed inhibitory effect on the post-prandial rise in plasma glucose. Sucrose loading in rats (about 443 mg) sharply increased blood glucose and was accompanied by the rapid disappearance of sucrose from the upper small intestine. AO-128 (0.03 or 0.1 mg/kg) lessened the elevation of blood glucose after sucrose ingestion. The lower dose (0.03 mg/kg) retarded small intestinal absorption, but did not induce an influx of sucrose into the cecum and large intestine, while the higher dose (0.1 mg/kg) caused an increased influx of sucrose into the large bowel. These results indicated that AO-128 retards the absorption of carbohydrate and reduces post-prandial hyperglycemia.
 ...
PMID:An alpha-glucosidase inhibitor, AO-128, retards carbohydrate absorption in rats and humans. 758 23

Eight non-insulin-dependent diabetes mellitus patients, in whom oral hypoglycaemic agents were not effective, were treated with an alpha-glucosidase inhibitor, AO-128 (0.9 mg/day) for 6 months. After 6 months of treatment there was a statistically significant decrease in the blood glucose level 1 and 2 h postprandially. The 2 h blood glucose level was also significantly reduced after 2 months' treatment. The insulin and HbA1c levels after 2 and 6 months' treatment were lower than those before administration. Faecal weight, the frequency of bowel movements, the ratio of hydroxy fatty acids to total fatty acids, and faecal short-chain carboxylic acid content were all increased significantly during treatment. The initially hard stools became normal or soft, although no actual diarrhoea developed. Both faecal bile-acid excretion and the ratio of primary bile acids to total bile acids were increased significantly after 2 months, but they showed some recovery towards the pretreatment levels after 6 months' treatment. There was no distinct change in neutral sterol and fatty acid excretion. Breath hydrogen excretion showed a slight increase after treatment. These results suggest that intestinal fermentation was promoted and the intestinal transit time was shortened by AO-128 administration.
 ...
PMID:Effect of an alpha-glucosidase inhibitor on intestinal fermentation and faecal lipids in diabetic patients. 811 83


<< Previous 1 2 3 4 5 Next >>