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)

Protein sulfation in small intestinal epithelial cells was studied by labelling of organ cultured mucosal explants with [35S]-sulfate. Six bands in SDS-PAGE became selectively labelled; four, of 250, 200, 166 and 130 kd, were membrane-bound and two, of 75 and 60 kd, were soluble. The sulfated membrane-bound components were all enriched in the microvillar fraction but either absent or barely detectable in intracellular or basolateral membranes. Immunopurification of sucrase-isomaltase, maltase-glucoamylase, aminopeptidase N and aminopeptidase A showed that these microvillar enzymes become sulfated. Most if not all the sulfate was bound to tyrosine residues rather than to the carbohydrate of the microvillar enzymes, showing that this type of modification can occur on plasma membrane proteins as well as on secretory proteins.
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PMID:Tyrosine sulfation, a post-translational modification of microvillar enzymes in the small intestinal enterocyte. 312 1

The results of studies on disaccharidase activities and on intestinal absorption in cases of complete and incomplete congenital small bowel obstruction are presented. Assays of the activities of maltase, isomaltase, sucrase, trehalase, and lactase have been performed on biopsy specimens taken at the time of surgery. In specimens taken from above the site of obstruction, the activities are reduced for all disaccharidases, and are particularly low for trehalase and lactase. There was no difference between the cases with complete and incomplete obstruction. Distal to a complete obstruction, trehalase and lactase were reduced, whereas in cases of incomplete obstruction, the activities of all disaccharidases were within what is considered normal in the reference material. Two months after surgery, the disaccharidase activities were found to be normal. One month after surgery, the absorption of glucose and vitamin A was markedly impaired in cases with complete obstruction, whereas that of D-xylose was not significantly reduced from normal. In cases with incomplete obstruction, the results did not differ from those found in normal infants. The fact that failure to thrive is common during the first months after birth in patients with congenital intestinal atresia, even when surgery is successful, may be explained by deficient intestinal absorption, particularly in patients with complete obstruction.
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PMID:Disaccharidase activities and intestinal absorption in infants with congenital intestinal obstruction. 312 31

Results of disaccharidase assays in small bowel biopsies from 887 children over a 3 year period were analysed to establish normal values. Abnormal histology, the presence of giardia trophozoites or total absence of sucrase and isomaltase were found in 307 cases and these were excluded from further consideration. The results for maltase, sucrase and lactase from the remaining 580 children have been graphed as percentiles at various ages. They represent results which are as close to normal as it is possible ethically to obtain.
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PMID:'Normal' disaccharidase levels in children. 312 60

1. The intestinal disaccharidase activities of a suckling crabeater seal were investigated. 2. Lactase, maltase, isomaltase and cellobiase activities were readily detected but trehalase and sucrase activities were absent. 3. The intestinal homogenates were separated into a soluble (S2) fraction and a particulate brush border (P2) fraction. The lactase activities of the two fractions had different properties corresponding to those of an acid and a neutral beta-galactosidase respectively. Approximately two-thirds of the total lactase activity measured at pH 6.0 was due to the acid beta-galactosidase. 4. The isomaltase and cellobiase activities were found almost exclusively in the particulate fractions but about one third of the maltase activity was in the S2 fraction. This soluble maltase activity appeared to be due to an acid maltase.
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PMID:Intestinal lactase and other disaccharidase activities of a suckling crabeater seal (Lobodon carcinophagus). 313 70

To assess the course of recovery of gluten sensitive enteropathy in adults, histological and functional recovery was studied in 22 patients, aged 20-79 years. Biopsy specimens taken at the time of diagnosis were studied in 20; after adhering to a gluten free diet for nine to 19 (mean 14) months in 14; and after adhering to the same diet for 24-48 (mean 34) months in 10 patients. Histological recovery was assessed morphometrically in the proximal jejunum. Mucosal linings significantly improved over time, but did not completely return to normal with a gluten free diet: at diagnosis the surface: volume ratio was 22% of normal, increasing to 48% and 66% after nine to 19 and 24-48 months, respectively, of a gluten free diet. Disaccharidase activities progressively increased. After 24-48 months maltase, sucrase, and isomaltase had returned to normal in the proximal jejunum; they were still significantly decreased in the distal duodenum. Duodenal and jejunal lactase activities were both below normal after 24 to 48 months. It is concluded that recovery of the intestinal mucosa of adults with gluten sensitive enteropathy during a gluten free diet continues beyond nine to 19 months and is still incomplete after two to four years. The recovery of disaccharidase activities extends from the distal to the proximal part of the small intestine, and is aligned to histological recovery.
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PMID:Slow and incomplete histological and functional recovery in adult gluten sensitive enteropathy. 317 Jul 77

Cell-associated oligo-1,6-alpha-glucosidase (EC 3.2.1.10) was isolated from Thermoanaerobium Tok6-B1 grown on starch-containing medium. Activity was purified 11.4-fold by salt precipitation, gel filtration, hydroxyapatite and anion-exchange chromatography. Molecular mass was determined as 30,000 by SDS/polyacrylamide-gel electrophoresis and 33,000 by analytical gel filtration. The probable order of specificity was p-nitrophenyl-alpha D-glucose greater than-isomaltose greater than-isomaltotriose greater than-panose greater than-nigerose and no activity was shown against malto-oligosaccharides, melezitose, melibiose, raffinose, cellobiose, sophorose, gentiobiose, lactose, pullulan, dextran or amylose. The optima for activity and stability were between pH 5.6 and 7.0 and the half-life at pH 6.5 was 1000 min at 70 degrees C and 20 min at 76 degrees C. Activity was stabilized by substrate, Mg2+, Mn2+ and Ca2+, but was destabilized by Zn2+ and EDTA. N-Ethylmaleimide, glucose and 1-O-methyl-alpha D-glucose were inhibitory but 1-O-methyl-beta D-glucose stimulated activity. The activation energy (Ea) was 109 kJ/mol.
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PMID:A cell-associated oligo-1,6-alpha-glucosidase from an extremely thermophilic anaerobic bacterium, Thermoanaerobium Tok6-B1. 321 28

MDL 25,637 is a novel compound designed as a transition-state inhibitor of alpha-glucohydrolases. This compound inhibits rat intestinal sucrase, maltase, isomaltase, glucoamylase and trehalase activities at micromolar concentrations. It is a much weaker inhibitor of alpha-amylase and lactase. Inhibition of sucrase was competitive with sucrose. In mice, MDL 25,637 inhibited the rise in serum glucose after a sucrose or starch load but not after a glucose load. MDL 25,637 also reduced the glycemic response to sucrose in rats. The drug was most effective when administered 0 to 30 min before the sucrose load and was as effective in streptozotocin-treated rats as in normals. The inhibition by MDL 25,637 of intestinal glucohydrolases is an effective means of reducing the hyperglycemic response to an oral sucrose or starch load and, as such, warrants further investigation as a potential drug for the treatment of diabetes mellitus.
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PMID:Inhibition of intestinal disaccharidases and suppression of blood glucose by a new alpha-glucohydrolase inhibitor--MDL 25,637. 329 22

1. Injection of hydrocortisone into 9-day-old rats induces the early appearance of sucrase in jejunal homogenates, the time course of the subsequent increase and magnitude of the final effect being similar to that seen to start on day 16 during normal development. 2. Cytochemical comparison of the effect of hydrocortisone and normal development on the appearance of a mixture of sucrase, maltase, isomaltase and trehalase disaccharidases (alpha-glucosidase activity) shows this enzyme to appear first in enterocytes at the base of the villus. Enzyme activity then increases and spreads along the whole villus during the next 96 h. 3. The rate at which enterocytes migrate along the villus after hydrocortisone injection is not significantly different from that measured during the early phase of normal development. The later phase of normal development is associated with a threefold increase in cell migration rate and a twofold increase in crypt depth. 4. The rate at which alpha-glucosidase activity increases in enterocytes at the base of the villus during early normal development is similar to that determined after hydrocortisone injection into younger animals. This rate of appearance increases eight to tenfold during normal development, shortly after the appearance of solid food in the stomach of normal control animals. 5. Injection of steroid hormones into young rats is generally supposed to mimic events taking place normally at weaning. Present results show alpha-glucosidase induction during normal development to be under more complicated control than had been previously suspected.
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PMID:Rat jejunal disaccharidase activity increases biphasically during early post-natal development. 332 44

Procedures have been validated for the investigation of the physical properties of canine microvillar membrane proteins by SDS-polyacrylamide gel electrophoresis. These have been used to examine mucosal samples from eight control dogs and from five dogs with naturally occurring exocrine pancreatic insufficiency (EPI) in order to evaluate the potential role of the pancreas in the normal turnover of microvillar membrane proteins in the dog. Gel scanning showed that the proportion of total membrane protein in bands corresponding to a molecular mass greater than 200 kDa was up to 20-times higher in dogs with EPI than in control dogs. In particular, a band of apparent molecular mass 218 kDa represented between 8 and 28% of membrane protein in all affected dogs, compared with only 0.5 to 1.8% in controls, and is most likely to contain single chains of both pro-maltase-glucoamylase and pro-sucrase-isomaltase. Incubation of microvillar membranes in vitro with either trypsin or canine pancreatic juice resulted in degradation of this high molecular mass band and a corresponding increase in the amount of protein in three bands representing molecular masses of 150, 133 and 106 kDa. In samples from control dogs aminopeptidase N was identified in the 133 kDa band by Western blotting and incubation with monospecific antiserum. These findings suggest that pancreatic enzymes play a major role in the normal post-translational processing of intestinal microvillar membrane proteins in the dog.
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PMID:Investigation of the physical properties of dog intestinal microvillar membrane proteins by polyacrylamide gel electrophoresis: a comparison between normal dogs and dogs with exocrine pancreatic insufficiency. 340 88

Acid alpha-glucosidase [EC 3.2.1.3] was purified from pig liver by a procedure including Sephadex G-100 affinity chromatography. Electrophoresis on SDS-polyacrylamide gel of the purified enzyme indicated the presence of two components with molecular weights of 73K and 64K. The two components of the enzyme were completely separated, in reasonable yield, by chromatography on a DEAE-5PW column. Both components catalyzed the hydrolysis of the alpha-1,4 and alpha-1,6 linkages of glycogen, maltose, isomaltose, dextrin, and a synthetic glucoside at acid pH. The pH optima of both components were 4.3 for maltase and glucoamylase, and 4.8 for isomaltase and dextrinase. But as to the activity on 4MU-alpha-Glc, the pH optimum of the larger component was 4.8 and that of the smaller component 5.3. The Km values of both components for 4MU-alpha-Glc, maltose, glycogen, isomaltose, and dextrin were 1.0 X 10(-4) M, 9.1 X 10(-3) M, 16.7 mg/ml, 6.7 X 10(-2) M, and 12.5 mg/ml, respectively. Erythritol, Tris, and turanose inhibited the two components competitively. The Ki values of the larger component were 5.0 X 10(-2) M, 13.3 X 10(-3) M, and 3.2 X 10(-3) M, and those of the smaller component were 2.5 X 10(-2) M, 6.1 X 10(-3) M, and 4.7 X 10(-3) M, for erythritol, Tris, and turanose, respectively.
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PMID:Purification and characterization of two components of acid alpha-glucosidase from pig liver. 351 91


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