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)

We synthesized o-(4,6-o-isopropylidene-alpha-D-glucopyranosyl)-(1----4)- [o-alpha-D-glucopyranosyl-(1----4])5-o-alpha-D-glucopyranosyl-(1----2)- alpha-D-fructofuranoside (IPG7F) and developed an assay for determining the activity of amylase in human serum and urine by using this substrate. Glucoamylase, alpha-glucosidase, and mannitol dehydrogenase are used as coupling enzymes. The coupled reactions are monitored by continuously measuring the oxidation rate of NADH. In this procedure, various substances in the test specimens do not interfere with the detection of amylase activity. Exactly one molecule of NADH is oxidized by one attack of amylase on the substrate, although four products can be produced in the reaction. The within-assay coefficient of variation (CV) ranged from 1.0% to 4.1% and the between-assay CV ranged from 2.6% to 5.3%. The results of our new assay correlate well with those of the amylase assay involving p-nitrophenol maltoheptaoside as substrate (r = 0.978) and with those of the amylase assay involving maltopentaose (r = 0.987).
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PMID:Isopropylidine maltoheptosyl fructofuranoside, doubly blocked substrate for determination of endoamylase activity. 171 59

Post-prandial glucose excursions remain elevated in most patients with diabetes even when normal fasting plasma glucose levels have been achieved. In 39 patients with type 2 diabetes who had attained basal normoglycaemia by therapy with diet alone, a sulphonylurea, a basal insulin supplement or basal plus prandial insulin the mean glycosylated haemoglobin (HbA1) values were at the upper end (mean +/- 1SD, 8.1 +/- 1.1%) of the normal range (5.0-8.2%). Miglitol, an alpha-glucosidase inhibitor, given in a dose of 50 mg three times a day was studied in a double blind randomized crossover study. In diet and sulphonylurea treated patients, a mean 25% reduction of the post-prandial plasma glucose excursions was obtained whereas in ultralente treated patients miglitol appeared to reduce basal plasma glucose levels (p < 0.006). Side effects were limited to minor gastrointestinal disturbances, usually ameliorating after the first week of therapy. Alpha-glucosidase inhibition to prevent post-prandial glycaemia may have a role in patients in whom sulphonylurea or diet therapy has been used to obtain normal basal glucose concentrations.
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PMID:Post-prandial glycaemic reduction by an alpha-glucosidase inhibitor in type 2 diabetic patients with therapeutically attained basal normoglycaemia. 184 49

Starch-degrading, amylolytic enzymes are widely distributed among microbes. Several activities are required to hydrolyze starch to its glucose units. These enzymes include alpha-amylase, beta-amylase, glucoamylase, alpha-glucosidase, pullulan-degrading enzymes, exoacting enzymes yielding alpha-type endproducts, and cyclodextrin glycosyltransferase. Properties of these enzymes vary and are somewhat linked to the environmental circumstances of the producing organisms. Features of the enzymes, their action patterns, physicochemical properties, occurrence, genetics, and results obtained from cloning of the genes are described. Among all the amylolytic enzymes, the genetics of alpha-amylase in Bacillus subtilis are best known. Alpha-Amylase production in B. subtilis is regulated by several genetic elements, many of which have synergistic effects. Genes encoding enzymes from all the amylolytic enzyme groups dealt with here have been cloned, and the sequences have been found to contain some highly conserved regions thought to be essential for their action and/or structure. Glucoamylase appears usually in several forms, which seem to be the results of a variety of mechanisms, including heterogeneous glycosylation, limited proteolysis, multiple modes of mRNA splicing, and the presence of several structural genes.
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PMID:Microbial amylolytic enzymes. 254 11

The human colon carcinoma cell line HT-29 differentiates into functional enterocytes upon replacement of glucose by galactose in the culture medium. Since the differentiation of other types of cells is associated with the modulation of 1,25-dihydroxycholecalciferol (1,25(OH)2D3) receptor concentrations and since enterocytes are classical target cells for 1,25(OH)2D3 we have examined the HT-29 cells to determine whether the differentiated and undifferentiated stages could be directly linked to the presence of 1,25(OH)2D3 receptors. HT-29 cells were grown in Dulbecco's modified medium containing 10% fetal calf serum (FCS) and glucose or galactose. Cell differentiation was assessed by measuring the brush border hydrolase, maltase. 1,25(OH)2D3 receptors were studied in the cells after 48 h without FCS. Nuclear uptake was measured in intact dispersed cells and the receptor protein was further characterized by vitamin D metabolite binding specificity, sucrose density gradient analysis and binding to DNA-cellulose. Maltase activity was 5-fold greater in differentiated HT-29 cells than in undifferentiated cells. Scatchard analysis showed a highly specific saturable (9500 sites per cell) high affinity (2 x 10(-10) M), binding of 1,25(OH)2D3 in undifferentiated cells. This receptor-like protein sedimented at 3.3S, bound to and eluted from DNA-cellulose and had all the characteristics of a 1,25(OH)2D3 receptor. No specific binding was detected in differentiated HT-29 cells. The presence of 1,25(OH)2D3 receptors in undifferentiated HT-29 cells implies that these cells are targets for vitamin D. The maltase activity increased significantly when undifferentiated cells were exposed to 1,25(OH)2D3 for 5-6 days, indicating that the hormone can promote differentiation of HT-29 cells. These results demonstrate that HT-29 cells can provide a new model for studying steroid receptor regulation and cell differentiation.
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PMID:Human colon cell line HT-29: characterisation of 1,25-dihydroxyvitamin D3 receptor and induction of differentiation by the hormone. 283 36

Trichosporon pullulans IGC 3488 produced extracellular alpha-amylase and glucoamylase activities when grown in batches in a medium containing corn steep liquor and soluble starch or corn starch. alpha-Amylase, unlike glucoamylase activity, was secreted biphasically. For both amylases the maximum concentration was found in stationary phase cultures. The amylolytic enzymes, previously concentrated by ammonium sulfate precipitation, were separated into a glucoamylase fraction and an alpha-amylase fraction by Ultrogel AcA 54 gel filtration. Pullulanase activity was located in the glucoamylase fraction, whereas cyclodextrinase activity was restricted to the alpha-amylase fraction. Isoamylase and alpha-glucosidase were not detected. Electrophoretic analysis showed that alpha-amylase activity was due to a single protein. Glucoamylase, however, occurred in multiple forms. The four glucoamylases and the alpha-amylase were glycoproteins.
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PMID:Secretion of alpha-amylase and multiple forms of glucoamylase by the yeast Trichosporon pullulans. 308 51

Studies of intestinal enzyme development and regulation relevant to the human infant require an animal model with a rate of maturation similar to that of the human infant. Hanford miniature pigs were weaned at 3 days of age to a standard swine weaning formula. At 1, 2, 3, 4, 5, and 6 wk of age, duodenal jejunal, and ileal segments were analyzed for protein content and lactase, sucrase, maltase, glucoamylase, and acid beta-galactosidase activities. Protein content of the small intestine changed significantly with age only in the ileum (p less than 0.05). Lactase activity fell significantly with age in all segments of the small intestine (p less than 0.001); activity was highest in the jejunum. Sucrase and maltase activities were present in all segments of the small intestine at 1 wk of age. Sucrase increased significantly (2-fold, p less than 0.02) with age only in the ileum and maltase increased significantly with age in the jejunum (by 50%, p less than 0.05) and the ileum (3-fold, p less than 0.001). Activities were highest in the jejunum. Glucoamylase activity was present at 1 wk of age and showed a small but significant increase with age only in the duodenum (p less than 0.005). Acid beta-galactosidase activity demonstrated small but significant decreases with age in all small intestinal segments. Glucoamylase and acid beta-galactosidase activities were similar in all segments. In the 6-wk-old pigs, activities of all the enzymes tested were similar to those found in young human infants.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The miniature pig as an animal model for the study of intestinal enzyme development. 312 4

Alpha-glucosidase inhibitors delay carbohydrate absorption. In order to study the effects of two new alpha-glucosidase inhibitors with long (BAYo1248) and short (BAYm1099) duration of action on glycaemic control, seventeen insulin-dependent diabetics were connected to the Biostator for 24 h and postprandial hyperglycaemia, insulin requirements and breath H2 concentrations were assessed under three conditions: (a) before administration of any alpha-glucosidase inhibitor (control experiments), (b) after administration of BAYo1248 (40 mg before breakfast, nine patients) or BAYm1099 (100 mg before breakfast and dinner, eight patients) for 1 month, (c) after 1-month administration of placebo (double-blind crossover study). All patients were on standard diets (30 kcal kg-1, 45% carbohydrate, 35% fat, 20% protein). BAYo1248 reduced postprandial hyperglycaemia and insulin requirements (vs. values in control and placebo experiments) after breakfast (124 +/- 8 vs. 159 +/- 8 and 158 +/- 8 mg dl-1, 16 +/- 2 vs. 24 +/- 4 and 23 +/- 3 units, P less than 0.01) and lunch (138 +/- 7 vs. 155 +/- 11 and 162 +/- 13 mg dl-1, 19 +/- 3 vs. 24 +/- 3 and 23 +/- 3 units, P less than 0.01) whereas BAYm1099 reduced postprandial hyperglycaemia and insulin requirements after breakfast (127 +/- 4 vs. 167 +/- 12 and 159 +/- 6 mg dl-1, 15 +/- 3 vs. 24 +/- 4 and 21 +/- 3 units, P less than 0.02) and dinner (128 +/- 4 vs. 169 +/- 7 and 157 +/- 10 mg dl-1, 19 +/- 2 vs. 28 +/- 3 and 25 +/- 2 units, P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of prolonged administration of two new alpha-glucosidase inhibitors on blood glucose control, insulin requirements and breath hydrogen excretion in patients with insulin-dependent diabetes mellitus. 313 Feb 57

p-Nitrophenyl O-(6-O-benzyl)-alpha-D-glucopyranosyl-(1----4)-O-alpha-D-glucopyranosyl- (1----4)-O-alpha-D-glucopyranosyl-(1----4)-O-alpha-D-glucopyranosyl-(1-- --4)-alpha-D-glucopyranoside (BG5P) is hydrolyzed by both human salivary alpha-amylase (HSA) and human pancreatic alpha-amylase (HPA) to O-(6-O-benzyl)-alpha-D-glucopyranosyl-(1----4)-O-alpha-D-glucopyranosyl- (1----4)-alpha-D-glucopyranose (BG3) and p-nitrophenyl alpha-maltoside (G2P). Glucoamylase and alpha-glucosidase cannot hydrolyze BG5P because of the modification of the OH group of the 6-position of the non-reducing-end glucose residue with the benzyl group. Taking advantage of these characteristics of the substrate, BG5P, we developed a method to assay the total alpha-amylase activity in human fluids using glucoamylase and alpha-glucosidase as the coupled enzymes. This method is simple and can be used as the standard method for routine clinical assays of alpha-amylase activity.
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PMID:Alpha-amylase assay with use of a benzyl derivative of p-nitrophenyl alpha-maltopentaoside, BG5P. 313 47

1. To evaluate the influence of age, DNA synthesis and brush border hydrolase activities were determined in mouse kidneys maturing in vivo and in serum-free organ culture. 2. DNA synthesis decreased with advancing age. 3. The protein content and leucylnaphthylamidase, maltase, trehalase, alkaline phosphatase and gamma-glutamyltransferase activities increased with aging. 4. The differences due to age were reproduced in kidneys maturing in culture. 5. These results show that age has a significant effect on the parameters determined, but apparently has no influence on the viability of the kidney explants in culture.
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PMID:Comparison between mouse kidneys of pre- and postnatal ages maturing in vivo and in serum-free organ culture. 322 12

The lysosomal enzymes cathepsin D (E.C. 3.4.23.5), alpha-glucosidase (E.C. 3.2.1.20) and beta-galactosidase (E.C. 3.2.1.23), potentially involved in the breakdown of the peptide component and the disaccharide units of basement membrane glycoproteins, were studied in the kidney cortex and liver of streptozotocin-diabetic mice. In the liver of diabetic mice, as compared to controls, an increase was found for the total activity (measured in frozen-thawed homogenates) of cathepsin D (+135%, P less than 0.01) and beta-galactosidase (+32%, P less than 0.05). In the kidney a decrease was observed for both the free activity (measured in 12,000 g supernatant) and the total activity of these two enzymes (cathepsin D: -62% and -24%; beta-galactosidase: -29% and -23%; P less than 0.05 in all instances). Alpha-glucosidase did not show significant changes in either tissues. Total protein content of the two organs did not change significantly with diabetes and therefore cannot account for the enzyme alterations observed. These data indicate that the response of kidney to diabetes is opposite to that of liver (decrease versus increase in catabolic enzymes), and suggest decreased degradation of basement membrane in some tissues in diabetes, which may contribute to the thickening of basement membrane and therefore to the development of microangiopathy.
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PMID:Cathepsin D and other hydrolases in the kidney of streptozotocin-diabetic mice. Possible relevance to microangiopathy. 393 Mar 80


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