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)

Ruminobacter amylophilus is an obligate anaerobe that uses only alpha-linked glucose molecules (i.e., maltose, maltodextrins, and starch) as a source of energy, making it an excellent model for the study of bacterial starch degradation. Constitutive amylase, amylopectinase, and pullulanase activities were found in intracellular and extracellular fractions of R. amylophilus. However, extracellular activities apparently resulted from cell lysis. Both soluble and membrane-bound polysaccharidase activities were detected. Most of the soluble polysaccharidase activity partitioned with the periplasmic cell fraction. No alpha-glucosidase or maltase activity was detected in either the cellular or extracellular fraction. In addition, intact cells of R. amylophilus bound U-14C-starch. This binding could be saturated and was constitutive and sensitive to proteinase K, indicating protein or protein complex mediation. Competition experiments showed that these starch-binding sites had equally high affinities for starch and maltodextrins larger than maltotriose. The sites had a reduced affinity for maltose and virtually no affinities for glucose and nonstarch polysaccharides. These findings suggest that R. amylophilus binds starch molecules to the cell surface as an initial step in transporting the molecule through the outer membrane and into the periplasmic space. Extracellular polysaccharides do not appear to be involved in starch degradation.
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PMID:Biochemical analysis of starch degradation by Ruminobacter amylophilus 70. 753 78

Activities of twelve hydrolytic enzymes in the digestive tract of young rabbits before weaning (4 weeks old) and adult rabbits (3 months old) were measured. The principal digestive enzymes in both groups of rabbits appeared to be amylase (EC 3.2.1.1), maltase (EC 3.2.1.20), pectinase (EC 3.2.1.15) and proteinases. The stomach of young rabbits contained most of the lipolytic activity and 45.7% of the total proteolytic activity of the digestive tract. The highest specific activities (per g digesta) of amylase, maltase and proteinase in young rabbits were found in the small intestine. Total activities (per segment) of amylase and maltase in the small intestine and the caecum were similar. Activities of cellulase (EC 3.2.1.4), inulinase (EC 3.2.1.7) and beta-glucosidase (EC 3.2.1.21) were low and activity of pectinase was fairly high in all segments of the digestive tract. The highest activity of urease (EC 3.5.1.5) was found in the caecum. Enzymic profiles of the colonic chymus resembled those of the caecum. Total hydrolytic activity was lower in the colon than in the caecum. Specific activities of amylase and invertase (EC 3.2.1.26) were lower and those of inulinase and lactase (EC 3.2.1.23) higher in 4-week-old rabbits than in 3-month-old rabbits. Gastric proteinase represented almost half of the total proteolytic activity of the digestive tract, whereas lipolytic activity of gastric contents was not found in measurable quantities in adult rabbits. The caecal contents of adult rabbits contained most of the total activity of lipase (EC 3.1.1.3), cellulase, xylanase (EC 3.2.1.32), pectinase, lactase, invertase, beta-glucosidase and urease present in the digestive tract.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Distribution of activity of hydrolytic enzymes in the digestive tract of rabbits. 753 89

To determine the prevalence of short polymers of glucose and starch malabsorption caused by small intestinal glucoamylase deficiency in children with chronic diarrhea, we studied small bowel biopsy specimens from 511 children (aged 1 month to 9 years) with chronic diarrhea evaluated at 54 medical centers. Glucoamylase and disaccharidase (lactase, sucrase, maltase, and palatinase) enzyme assays were performed. Of the 511 children, 15 had glucoamylase deficiency. Six who had significant small intestinal mucosal injury and disaccharidase deficiencies were defined as having secondary glucoamylase deficiency; the other nine patients with normal mucosal morphologic features were defined as having primary glucoamylase deficiency. Secretin tests showed normal pancreatic amylase values for age in all seven children tested. Four of them had abnormal findings on tolerance tests for starch and short polymers of glucose (rise in blood glucose concentration: < 20 mg/dl) and reducing substances in stools, and three of these four had symptoms of intolerance (abdominal distention, flatulence, and diarrhea). All seven patients responded to a starch elimination diet. After reintroduction of a starch diet, diarrhea recurred in four patients; this was alleviated 48 hours after reelimination of starch. We conclude that intestinal glucoamylase deficiency is present in some patients with chronic diarrhea.
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PMID:Small intestinal glucoamylase deficiency and starch malabsorption: a newly recognized alpha-glucosidase deficiency in children. 815 67

We describe a reagent for measuring alpha-amylase (EC 3.2.1.1) activity in serum with use of a thexyldimethylsilyl ether of p-nitrophenyl-alpha-D-maltoheptaoside (SB7) as substrate. This substrate differs from Genzyme's benzylidene-blocked p-nitrophenylmaltoheptaoside substrate (B-PNPG7). The reagent, optimized for the characteristics of the silyl-blocked substrate, contains 4-(2-hydroxyethyl)-1-piperazineethane sulfonate buffer at pH 7.3, alpha-glucosidase (maltase; EC 3.2.1.20), and glucoamylase (EC 3.2.1.3). Comparison with Ciba Corning Diagnostics Corp.'s, amylase reagent with B-PNPG7 as substrate (x) yielded a regression equation of y = 1.20x-2.7 (r = 0.9997). The linear range exceeded amylase concentrations > 2500 U/L and total precision (CV) was 2.3% at an amylase concentration of 112 U/L with the Ciba Corning 550 Express analyzer. Reconstituted reagent is stable for 30 days at 5 degrees C and 7 days at ambient (18-25 degrees C) temperatures.
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PMID:Evaluation of silyl-blocked p-nitrophenylmaltoheptaoside as a substrate for alpha-amylase reagents. 841 32

1. Body weight, digestive organ weights, and activities of disaccharidases (maltase and saccharase) activities were determined from day of hatch to 21 d of age in meat- and egg-type chickens. Blood plasma was analysed for enzyme activities and metabolite concentration. 2. In meat-type chickens food intake and growth rate were about 3-fold those in egg-type chickens. Food efficiency was superior in meat-type chickens throughout the experimental period. 3. Meat-type chickens hatched with disaccharidase activities exceeding those found in their egg-type counterparts 2- to 5-fold. From 7 d of age on, this trend reversed, i.e. activity was much higher in egg-type than in meat-type chickens. 4. Blood plasma amylase activity increased gradually in meat-type chickens and was higher than in egg-type chickens to 14 d of age. No breed differences were observed for alkaline phosphatase or lactate dehydrogenase activities during the experimental period. 5. Blood plasma concentrations of total protein, albumin, glucose, and calcium, were lower in meat than in egg-type chickens.
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PMID:Comparative development of digestive organs, intestinal disaccharidases and some blood metabolites in broiler and layer-type chicks after hatching. 877 45

The nucleotide sequence of a 1.5-kb fragment of the promoter region of the Aspergillus oryzae agdA gene encoding alpha-glucosidase was determined. A comparison with the promoter regions of other Aspergillus amylase genes indicated that there are three highly conserved sequences, designated Regions I, II and III, located at -670 nt, -596 nt and -544 nt relative to the start codon, respectively. The function of these consensus sequences in the agdA promoter was investigated by deletion analysis of a promoter fusion with the Escherichia coli uidA gene, using the niaD homologous-transformation system. Deletion of the upstream half of Region III (IIIa; -544 to -529) resulted in a more than 90% reduction in GUS activity and abolished maltose induction, suggesting that Region IIIa is a functionally essential element for high-level expression and maltose induction. Deletion of Region I and the downstream half of Region III (IIIb; -521 to -511) resulted in a significant reduction in GUS activity, but did not affect maltose induction. This suggested that these two elements most likely contain sequences involved in efficient expression in cooperation with Region IIIa. In addition, deletion of a 340-bp region between Region IIIb and the putative TATA box resulted in a 2-fold increase in activity.
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PMID:Deletion analysis of promoter elements of the Aspergillus oryzae agdA gene encoding alpha-glucosidase. 892 96

The objective of this study was to investigate the effects of L-arabinose on intestinal alpha-glucosidase activities in vitro and to evaluate its effects on postprandial glycemic responses in vivo. L-Arabinose inhibited the sucrase activity of intestinal mucosa in an uncompetitive manner (Ki, 2 mmol/L). Neither the optical isomer D-arabinose nor the disaccharide L-arabinobiose inhibited sucrase activity, whereas D-xylose was as potent as L-arabinose in inhibiting this activity. L-Arabinose and D-xylose showed no inhibitory effect on the activities of intestinal maltase, isomaltase, trehalase, lactase, and glucoamylase, or pancreatic amylase. In contrast, a known alpha-glucosidase inhibitor, acarbose, competitively inhibited (Ki, 1.1 mumol/L) sucrase activity and also inhibited intestinal maltase, glucoamylase, and pancreatic amylase. L-Arabinose suppressed the increase of blood glucose after sucrose loading dose-dependently in mice (ED50, 35 mg/kg), but showed no effect after starch loading. The suppressive effect of D-xylose on the increase of blood glucose after sucrose loading was 2.4 times less than that of L-arabinose, probably due to intestinal absorption of the former. Acarbose strongly suppressed glycemic responses in both sucrose loading (ED50, 1.1 mg/kg) and starch loading (ED50, 1.7 mg/kg) in mice. L-Arabinose suppressed the increase of plasma glucose and insulin in rats after sucrose loading, the suppression of the former being uninterruptedly observed in mice for 3 weeks. Thus, the results demonstrated that L-arabinose selectively inhibits intestinal sucrase activity in an uncompetitive manner and suppresses the glycemic response after sucrose ingestion by inhibition of sucrase activity.
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PMID:L-arabinose selectively inhibits intestinal sucrase in an uncompetitive manner and suppresses glycemic response after sucrose ingestion in animals. 893 41

Computerized tomography and ultrasound are helpful in the diagnosis of acute pancreatitis. The procedures, however, are not always available and so laboratory tests continue to play an important role. Serum amylase measurement is the most widely used test, despite its lack of sensitivity (75-92%) and specificity (20-60%). A cut-off point of 3-6 times the upper reference limit increases the specificity greatly, but at the expense of sensitivity. A method using chloronitrophenyl-maltotrioside as substrate has recently been rejected by the IFCC. A method using ethylidene-protected 4-nitrophenyl-maltoheptaoside and a new alpha-glucosidase has emerged as the method of choice. Amylase isoenzyme determinations have higher specificity than total amylase measurements. Serum lipase methods are more sensitive and specific, but methodological problems persist. Cationic trypsin-1 measurements yield high sensitivity but low specificity. Elastase-1 is claimed to correlate best with the clinical symptoms. Reasons for the widely differing reports on sensitivity and specificity of tests for pancreatitis are discussed.
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PMID:Support of the diagnosis of pancreatitis by enzyme tests--old problems, new techniques. 902 27

The effect of supplementing a cornsoybean diet (C) with glucose (G) or maltose (M) on young broilers (from hatch to 3 wk of age) affected by stunting syndrome (SS) was studied. Stunting syndrome was induced by orally administering an inoculum prepared from the intestines of SS broiler chicks. Relative to the M diet, the G diet improved growth and feed utilization and increased feed intake in naive (NA) control chickens. The C diet was intermediate in this respect. In contrast to the NA chickens, diet did not affect growth or feed utilization in SS chicks. Changes in the relative weights of the gastrointestinal tract segments were evident by 1 wk of age and hypertrophy of these segments persevered to 3 wk of age. Stunting syndrome infection was accompanied by a significant increase in pancreatic trypsin-specific activity during Weeks 1 and 2, and in chymotrypsin activity at 1 wk. During this time, amylase-specific activity was not affected. At 3 wk of age, the specific activities of amylase, trypsin, and chymotrypsin in the pancreas were lower in the inoculated vs control birds. Whereas no significant effect of SS was observed with activities of amylase in the intestinal contents, trypsin activity was higher in SS chicks at 1 wk, and that of chymotrypsin lower during Weeks 2 and 3. Relative to NA chicks, the maltase and saccharase activities of SS chicks were much lower during Week 1, but increased later on and were similar to NA chick values at 2 and 3 wk. Whereas the level of blood plasma proteins did not vary from 1 to 3 wk in the NA chicks, it increased gradually in SS chicks to a level that significantly exceeded that in their NA counterparts. Blood plasma glucose and triglyceride levels were slightly lower in the SS chicks (NS), and the blood plasma cholesterol level was significantly reduced during Week 2. Relative to NA chicks, SS infection caused a significant increase in plasma calcium during Weeks 2 and 3, accompanied by a significant reduction in blood plasma phosphorus at 2 wk only. No difference was observed in the blood plasma level of uric acid, which peaked in both treatments during Week 2, or in D-beta-hydroxybutyric acid level, which was quite stable during the experimental period. Stunting syndrome infection was accompanied by a dramatic increase in amylase and alkaline phosphatase activities in the blood plasma, and by a slight but significant decrease in activity of lactic dehydrogenase. Stunting syndrome was concluded to be an affliction not only of digestion but also of metabolism. The main depression in growth caused by SS inoculation is probably due to metabolic alterations beyond those of digestion and absorption.
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PMID:Stunting syndrome in broilers: effect of glucose or maltose supplementation on digestive organs, intestinal disaccharidases, and some blood metabolites. 905 21

Starch supported growth of continuous cultures of Bacteroides ovatus when this carbohydrate provided the sole source of carbon and energy. Inducible amylase and alpha-glucosidase activities were inversely related to dilution rate in starch-limited and starch-excess chemostats over the dilution rate (D) range D = 0.03/h to D =0.20/h, and were partly repressed during growth under conditions of starch-excess. Preparative isoelectric focusing of B. ovatus cytoplasmic extracts indicated the existence of three distinct starch-hydrolyzing enzymes. Incubation of active fractions from the isoelectric focusing cell with maltose and a variety of low-molecular-weight oligosaccharides (maltotriose, maltotetraose, maltopentaose, maltohexaose, maltoheptaose) identified a single amylase activity, an enzyme with combined beta-amylase and glucoamylase/alpha-glucosidase properties, and also a possible pullulanase. The ability of B. ovatus to synthesize several starch-hydrolyzing enzymes with different specificities and activities may confer a significant competitive advantage to this organism in the colonic ecosystem.
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PMID:Starch utilization by Bacteroides ovatus isolated from the human large intestine. 909 29


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