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 neutralization of acid introduced into the duodenum has been found to be less intensive in patients with duodenal ulcer than in controls. The present work studied the possibility that chronic gastric hypersecretion injures the duodenal mucosa and thereby influences the neutralization system. Gastric hypersecretion was provoked for 3 weeks in 3 dogs by a daily injection of a gastrin preparation with prolonged effect. After a subcutaneous injection of this preparation given together with a test meal the acidity of both gastric and duodenal contents was found to increase significantly. After the 3 weeks of gastric hypersecretion the pancreatic bicarbonate response to exogenous secretin was unchanged, while the bicarbonate response to duodenal acidification was decreased from 2.03 mEq/30 min to 1.27 mEq/30 min (p less than 0.05), compatible with an impaired secretin release. Also the concentration of lactase, maltase, sucrase, and alkaline phosphatase in mucosal biopsies from the second part of the duodenum was significantly reduced (p less than 0.001). These results indicate that gastric hypersecretion causes mucosal damage in the duodenum and thereby reduces the release of secretin.
 ...
PMID:Effect of gastric hypersecretion on the canine duodenum. 1 Jun 21

Three cassava fermentation methods (spontaneous fermentation, back-slopping and the use of starter culture) for the production of kivunde, executed in three trials at 30 degrees C, were compared in terms of cyanide level reduction, microbiology and product quality improvement. Among the isolates from spontaneously fermented cassava batches, four strains were selected on the basis of their enzymatic activities and acid production. All were identified as Lactobacillus plantarum and were used as starters in this study. Lowest residual cyanide levels were detected after 120 h fermentation time in samples fermented with the starter culture and were below the maximum value of 10 mg/kg recommended by the Codex/FAO for cassava flour. This finding seems to be related to the alpha-glucosidase activity of the inoculated strains of which API-zyme (Bio-Merieux) tests showed activities of between 20 and > or = 40 nmol/4 h. The total residual cyanide levels of the spontaneous and back-slopping fermentations at 96 h were respectively 43.5 and 47.7 mg/kg dry weight of cassava. Extension of the fermentation period to 5 days, lead to further substantial reduction in the residual cyanide level in both these processes, but not below the recommended maximum value as in the case of starter culture fermented products. The spontaneous and back-slopping fermented cassava showed signs of deterioration after 3 days of fermentation. There was a sharp drop of pH and an increase of titratable acidity for all three batches during the first 48 h followed by a slow rise of pH and drop in titratable acidity towards the end of fermentation. The samples fermented with the starter culture had a smooth texture and pleasant fruity aroma, as opposed to the course and dull appearance and more complex flavour of the samples of spontaneous and back-slopping batches. During fermentation with starter culture, Enterobacteriaceae and yeasts and moulds could not be isolated throughout the period of fermentation (detection limit: 10 colony forming units/g). The present findings indicate the suitability of these Lb. plantarum strains as starter cultures for cassava fermentation in the kivunde process. The paper highlights the potential for the improvement of a traditional African fermented food (kivunde) through the use of a starter culture.
 ...
PMID:The use of a starter culture in the fermentation of cassava for the production of "kivunde", a traditional Tanzanian food product. 1085 44

The solvent kinetic isotope effects (SKIE) on the yeast alpha-glucosidase-catalyzed hydrolysis of p-nitrophenyl and methyl-d-glucopyranoside were measured at 25 degrees C. With p-nitrophenyl-D-glucopyranoside (pNPG), the dependence of k(cat)/K(m) on pH (pD) revealed an unusually large (for glycohydrolases) solvent isotope effect on the pL-independent second-order rate constant, (DOD)(k(cat)/K(m)), of 1.9 (+/-0.3). The two pK(a)s characterizing the pH profile were increased in D(2)O. The shift in pK(a2) of 0.6 units is typical of acids of comparable acidity (pK(a)=6.5), but the increase in pK(a1) (=5.7) of 0.1 unit in going from H(2)O to D(2)O is unusually small. The initial velocities show substrate inhibition (K(is)/K(m) approximately 200) with a small solvent isotope effect on the inhibition constant [(DOD)K(is)=1.1 (+/-0.2)]. The solvent equilibrium isotope effects on the K(is) for the competitive inhibitors D-glucose and alpha-methyl D-glucoside are somewhat higher [(DOD)K(i)=1.5 (+/-0.1)]. Methyl glucoside is much less reactive than pNPG, with k(cat) 230 times lower and k(cat)/K(m) 5 x 10(4) times lower. The solvent isotope effect on k(cat) for this substrate [=1.11 (+/-0. 02)] is lower than that for pNPG [=1.67 (+/-0.07)], consistent with more extensive proton transfer in the transition state for the deglucosylation step than for the glucosylation step.
 ...
PMID:Solvent isotope effects on alpha-glucosidase. 1558 3

The human ileocaecal adenocarcinoma cell line HCT-8 was characterized for its potential as an in vitro organ-specific model for gastro-intestinal toxicity. HCT-8 cells showed typical epithelial cell morphology, with microvilli and intercellular junctional complexes, and formed domes, consistent with transepithelial fluid secretion. The cells express three intestinal brush-border enzyme activities (alkaline phosphatase, leucine aminopeptidase and alpha-glucosidase), and adenylate cyclase can be stimulated with vasoactive intestinal peptide. The toxicity of eight non-steroidal anti-inflammatory drugs (NSAID; indomethacin, mefenamic acid, ketoprofen, ibuprofen, sulindac, aspirin, phenylbutazone and naproxen) were assessed using the MTT and neutral red uptake assays. The MTT assay was consistently a more sensitive measure of NSAID-induced toxicity, which suggests that perturbation of mitochondrial function may be an early event in NSAID-induced cellular damage. Comparing the rankings observed in acute studies in the rat in vivo with those observed with HCT-8 cells, there are some general agreements. Indomethacin, a potent ulcerogen in vivo, was consistently among the most toxic in vitro, while aspirin and phenylbutazone have comparatively low rankings in vitro and in vivo. In man, with chronic administration, indomethacin is again ranked as a potent ulcerogen, as is aspirin, in contrast to the in vitro data with HCT-8. Therefore, NSAID-induced toxicity in HCT-8 cells assessed by the MTT or neutral red assays, can only partially predict toxicity in vivo, which suggests that local gastro-intestinal environmental factors, such as luminal acidity, may play a role in vivo. The ability of HCT-8 cells to reconstitute intact epithelial layers, thereby allowing such environmental factors to be mimicked, allows further development of these cells as a model for the in vitro prediction of in vivo gastro-intestinal toxicity.
 ...
PMID:Toxic effects of non-steroidal anti-inflammatory drugs in a human intestinal epithelial cell line (HCT-8), as assessed by the MTT and neutral red assays. 2073 14