Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Acarbose, a potent alpha-glucosidase inhibitor, represents a new concept for the treatment of metabolic disorders, and particularly diabetes mellitus. It slows the absorption kinetics of dietary carbohydrates by reversible competitive inhibition of alpha-glucosidase activity, and so reduces the post-prandial blood glucose increment and insulin response. For these reasons, the drug has been successfully used not only in the treatment of type I or type II diabetes, but also in the management of reactive hypoglycemias and dumping syndrome. In addition, some data suggest a possible role in the treatment of type IV hyperlipidemia. Because of the delay in absorption of oligo- and disaccharides resulting from its administration, a colic bacterial fermentation occurs, accounting for the frequent abdominal discomfort mentioned by the patients. These side effects would be lessened with the second generation glucosidase inhibitors now in progress.
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PMID:[Alpha-glucosidase inhibitors: a new therapeutic approach in diabetes and functional hypoglycemia]. 267 46

An acid alpha-glucosidase (EC 3.2.1.20) was purified to homogeneity from the culture medium of Tetrahymena thermophila CU 399. Its general molecular, catalytic and immunological properties were compared to those of the T. pyriformis W enzyme. The enzyme from T. thermophila was a 105-kD monomer and the N-terminus (25 amino acid residues) displayed some homology with that of T. pyriformis enzyme. The purified enzyme was most active at 56 degrees C and showed resistance to thermal inactivation. The acid alpha-glucosidase appears to have alpha-1,6-glucosidase as well as alpha-1,4-glucosidase activity. The Km values determined with p-nitrophenyl-alpha-glucopyranoside, maltose, isomaltose and glycogen were 0.7 mM, 2.5 mM, 28.5 mM and 18.5 mg/ml, respectively. The enzyme was antigenically distinct from T. pyriformis acid alpha-glucosidase.
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PMID:A thermostable acid alpha-glucosidase from Tetrahymena thermophila: purification and characterization. 268 37

The effects of hydrocortisone and insulin on the intestinal brush border membrane enzymatic activities in an anuran amphibian, Alytes obstetricans, were investigated at the end of spontaneous metamorphosis and 2 weeks after its completion. At the end of metamorphosis, the brush border is differentiating in the apical region of a developing neoformed epithelium. Two weeks after the completion of metamorphosis, this epithelium is entirely formed. The animals received one hormone injection per day for 2 or 3 days running (hydrocortisone: 1, 5, or 25 micrograms/g body wt/day; insulin: 0.5, 1, or 5 mU/g body wt/day). The hydrolases studied were three glucosidases (maltase, glucoamylase, trehalase), gamma-glutamyl-transferase and alkaline phosphatase. In animals reaching the end of metamorphosis, hormonal treatments rarely modify the three glucosidase activities. Two weeks after metamorphosis, a 5 microgram/g body wt/day hydrocortisone injection usually results in a significant increase of the three glucosidase activities. Conversely, a 0.5 mU/g body wt/day insulin injection induced a marked decrease in these activities. At the end of metamorphosis, hydrocortisone has variable effects on gamma-glutamyl-transferase activity; insulin, however, does not significantly modify this activity. Two weeks later, insulin and sometimes hydrocortisone inhibit gamma-glutamyl-transferase activity. Whatever the developmental stage is, hydrocortisone is able to stimulate alkaline phosphatase activity. At the end of metamorphosis, insulin has no influence on this activity, but 2 weeks after metamorphosis, low doses of the hormone (0.5 mU/g body wt/day) significantly reduce it. These results emphasize the possibility that after spontaneous metamorphosis the enzymatic activities of the new intestinal brush border are hormone controlled. This control could be related to the development of the interrenal and pancreatic islet functions.
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PMID:Hormonal control of the intestinal brush border enzyme activities in developing anuran amphibians. I. Effects of hydrocortisone and insulin during and after spontaneous metamorphosis. 286 4

Peptide YY (PYY) is a recently discovered peptide found in the distal ileum and colon. It circulates in plasma and concentrations rise in malabsorptive conditions. The potential of PYY as an indicator of impaired carbohydrate digestion was studied in a pharmacological model of intestinal glucosidase inhibition. Thirteen type-2 diabetics on long-term treatment with the alpha-glucosidase inhibitor acarbose (3 x 100 mg per day) had test meals with and without acarbose 100 mg before and after the treatment period (mean 46 weeks), a test meal with acarbose after 20 weeks of continuous treatment and a final test meal without acarbose 6 weeks after cessation of treatment. Without acarbose mean plasma PYY concentrations rose from a mean basal value of 11.5 +/- 2.9 pmol/l to 19.5 +/- 3.9 pmol/l 120 min postprandially (P less than 0.01). Acarbose treatment did not effect basal plasma PYY concentrations but significantly enhanced food stimulated PYY concentrations acutely, at 20 weeks and at the final treatment test meal. Mean incremental integrated plasma responses (area under curve) rose by 183%, 184% and 169%, respectively (P less than 0.05). After cessation of treatment postprandial responses returned to pretreatment values within 6 weeks. Conversely, the integrated incremetal postprandial plasma responses of glucose and insulin were reversibly reduced by acarbose to 58% +/- 9% and 60% +/- 10% of controls, respectively. Self-assesed side effects of flatulence and more frequent bowel action showed no regular relationship to the PYY response. PYY seems to act as an indicator of the increased carbohydrate load to the distal intestine even in the absence of clinical symptoms. It may contribute to the hypoglycaemic effect of alpha-glucosidase inhibitors by slowing down intestinal transit.
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PMID:Peptide YY in diabetics treated chronically with an intestinal glucosidase inhibitor. 305 80

Postprandial hyperglycemia in diabetic patients can be modified by delaying the digestion and/or absorption of dietary carbohydrates. We have studied an orally active alpha-glucosidase inhibitor, Bay 1099, in normal volunteers to determine whether these inhibitors can decrease postprandial rises in serum glucose without causing gastrointestinal symptoms or significant fecal caloric wastage. Six subjects were given 25, 50, or 100 mg of Bay 1099 or placebo before meals for 1 week, each with a 1-week washout period. Fasting and postprandial concentrations of glucose, insulin, glucagon, enteroglucagon, and gastrointestinal inhibitory peptide (GIP) were measured after the first and last dose of Bay 1099, and the fecal excretions of protein, fat, fiber, and total calories were measured on the last three days of each diet. The passage of unabsorbed carbohydrate into the colon was determined by breath hydrogen analysis three times during each study week. Increasing doses of Bay 1099 were found to decrease the postprandial rise in serum glucose concentration, delay the time to peak insulin concentration, and decrease the output of GIP after the meal. No adaptation was apparent after 1 week of therapy. A dose of inhibitor (50 mg tid), which greatly improves postprandial glucose and hormone output in diabetes, was associated with minimal symptoms and no excess fecal caloric losses. Thus, glucosidase inhibitors such as Bay 1099 may be useful in the management of patients with carbohydrate intolerance.
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PMID:Intestinal and metabolic responses to an alpha-glucosidase inhibitor in normal volunteers. 305 29

Cultured skin fibroblasts derived from patients with cystic fibrosis contain 2.1-fold more acid alpha-glucosidase (EC 3.2.1.3) than normal fibroblasts. This difference is amplified to 2.3-fold when the cells are extracted in Triton X-100. In a study of 14 fibroblast cell lines derived from CF homozygotes and heterozygotes, normal individuals and patients with other recessively inherited disorders, normal individuals could be distinguished from either CF homozygotes or heterozygotes based on the ratio of acid alpha-glucosidase to beta-hexosaminidase when fibroblasts were extracted in either water or Triton X-100. However, the best distinction could be made with water extracts as there was no overlap among individual data points in the three categories. The acid to neural alpha-glucosidase ratio only distinguished CF homozygotes from normal individuals when cells were extracted in Triton X-100. The use of a ratio relationship of acid alpha-glucosidase with beta-hexosaminidase allows the comparison of data from multiple experiments on different days of assay and on cells at different passage numbers. These results suggest that alpha glucosidase may have a role in the primary defect in cystic fibrosis.
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PMID:Alterations in specific activity of lysosomal alpha-glucosidase in cystic fibrosis. 307 37

The intestinal first pass metabolism of amygdalin has been investigated in rat small intestine in vitro. The results show that amygdalin is hydrolyzed to prunasin, essentially in the wall of the proximal jejunum. This specific beta(1-6)hydrolytic cleavage of the terminal glucose residue is pH-dependent and can be inhibited by glucono-delta-lactone, a potent inhibitor of the lysosomal beta-glucosidase of the rat intestine. No substrate competition between phloridzin and lactose vs amygdalin was noted. None of the more common soluble beta- or alpha-enzymatic activities of mammalian intestine (alpha-glucosidase, alpha-amylase) or mammalian liver (beta-galactosidase, beta-glucuronidase) were capable of catalyzing the hydrolysis of the terminal glucose from amygdalin at pH's 5.0, 7.0 or 9.0. Furthermore, no metabolic activity of isolated rat livers toward amygdalin and prunasin was observed within two hours of recirculating perfusion. However, cecal contents of conventional rats, exhibited both amygdalin- and prunasin-hydrolyzing activities. The resulting mandelonitrile dissociates spontaneously into cyanide and benzaldehyde. Therefore, our findings indicate that metabolism of amygdalin to prunasin occurring in the proximal part of jejunum is apparently mediated by enzymatic beta(1-6)glucosidase activity of the gut wall. In contrast, the toxicity of amygdalin due to the release of cyanide obviously requires microbiological activities of the gut flora.
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PMID:Intestinal first pass metabolism of amygdalin in the rat in vitro. 308 25

L-carnitine, alpha,1-4-glucosidase, and glycerylphosphorylcholine were measured in seminal plasma of a selected group of azoospermic men and in an unselected group of oligozoospermic men. In vasectomized subjects the epididymal indices (mean +/- standard error: L-carnitine, 276.9 +/- 27.5 nmol/ejaculate; alpha-glucosidase, 1.2 +/- 0.1 U/ejaculate; and glycerylphosphorylcholine, 1.5 +/- 0.2 mumol/ejaculate) were always below the normal range of fertile subjects (1757.4 +/- 76.7 nmol/ejaculate; 16.4 +/- 0.9 U/ejaculate; and 17.3 +/- 0.7 mumol/ejaculate, respectively). On the contrary in a large number of patients affected by azoospermia because of seminiferous tubular damage (750.4 +/- 83.6 nmol/ejaculate; 6.8 +/- 0.9 U/ejaculate; and 6.1 +/- 0.6 mumol/ejaculate; respectively) and in a few oligozoospermic subjects (1193.7 +/- 72.3 nmol/ejaculate; 10.3 +/- 0.7 U/ejaculate; and 10.8 +/- 0.7 mumol/ejaculate; respectively) the epididymal indices were found in the range of vasectomized subjects, showing an association between seminiferous tubular lesion and epididymal dysfunction. In conclusion, in spite of the low levels of epididymal indices found in patients with obstructive azoospermia, the presence of a large number of subjects with seminiferous tubular lesions without obstruction with similar low values of L-carnitine, alpha-glucosidase, and glycerylphosphorylcholine reduces the usefulness of these indices in differential diagnosis of azoospermia.
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PMID:Simultaneous measurement of seminal L-carnitine, alpha,1-4-glucosidase, and glycerylphosphorylcholine in azoospermic and oligozoospermic patients. 310 88

The dansyl derivative of glucosyl galactosyl hydroxylysine (GGH) was separated into two components, as GP-I (monodansyl GGH) and GP-II (didansyl GGH) by paper chromatography. GP-I was further fractionated into four peaks (a, b, c and d) by reversed-phase liquid chromatography. These peaks corresponded to the dansyl derivatives at the alpha-amino (a and b) and epsilon-amino (c and d) groups of their hydroxylysine residues. There is the possibility that the fractions for b and d are diastereoisomers of a and c, respectively, since the monodansyl derivative from human urine consists of a and c. GP-II was fractionated into two peaks, e and f, which may possibly be diastereoisomers of each other. Treatment of the a, b, c and d fractions with crude chicken liver enzyme resulted in the preferential cleavage of a and b and the production of monodansyl galactosyl hydroxylysine. Components c and d were also cleaved slowly, resulting in the production of monodansyl hydroxylysine by the successive action of beta-galactosidase on dansyl galactosyl hydroxylysine. The detected alpha-glucosidase activity was strongly inhibited by free mannosamine. The method developed using the monodansyl GGH fraction a (or b) and high-performance liquid chromatography facilitated the detection of alpha-1,2-glucosidase, which acts specifically toward GGH even in a crude enzyme preparation.
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PMID:Subfractionation of the dansylated derivatives of glucosyl galactosyl hydroxylysine by liquid chromatography and its application to a specific alpha-1,2-glucosidase assay. 329 91

Intestinal adaptation (small intestinal weight and length, weight of the caecum and of the residual colon) to feeding different doses (0-5-50-500 mg/kg bw) of the absorbable, competitive alpha-glucosidase inhibitors BAY m 1099 and BAY o 1248 for three, seven, or 28 days was studied in rats. With the highest dose of either inhibitor, a significant and time dependent growth of the caecum was observed. Under these conditions, caecal tissue polyamine concentrations (spermidine and spermine) were slightly higher after three, unaffected after seven and slightly decreased after 28 days. Comparing the trophic effect both of BAY m 1099 and BAY o 1248 with that of the almost unabsorbed glucosidase inhibitor acarbose in fed rats showed that caecal weight was higher in response to the absorbed compounds than in response to acarbose, while total caecal carbohydrate content was unaffected by the absorbed and about nine fold increased by the unabsorbed inhibitors. These findings suggest that acarbose may partially inhibit bacterial carbohydrate degradation in the caecum.
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PMID:Adaptive responses to pharmacological inhibition of small intestinal alpha-glucosidases in the rat. 331 10


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