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)

The polybasic macromolecules DEAE-dextran (diethylaminoethyl-dextran, molecular weight 500000) and poly-DL-lysine (molecular weight 30000-70000) were absorbed with a high affinity by spheroplasts of Candida utilis and subsequently, induced lysis. The extent of lysis of spheroplasts and of the liberated vacuoles was studied under various conditions using alpha-glucosidase activity and soluble arginine as cytoplasmic and vacuolar markers, respectively. Adsorption of polybases was rapidly completed even at 0 degrees C; however, with small doses, lysis was poor at 0-12 degrees C and extensive at temperatures above 12 degrees C. This permitted the completion of adsorption before initiating lysis. The purified vacuoles were also sensitive to polybases though less so than the spheroplasts; however, after lysis of spheroplasts the liberated vacuoles were well protected against the action of polybases. A treatment with polybases which disrupted more than 99% of the spheroplasts left at least 70% of the vacuoles intact. Potassium chloride in high concentrations and calcium chloride in low concentrations inhibited polybase induced lysis of spheroplasts by preventing or even reversing the polybase adsorption. A polyacidic macromolecule, dextran sulfate, could prevent but not reverse the adsorption of polybase and subsequent lysis. Metabolic inhibitors reduced the susceptibility of spheroplasts to polybase induced lysis. Vacuoles isolated from polybase lysed spheroplasts still contained large pools of soluble amino acids, and their ability to transport arginine specifically is a further indication of their functional integrity.
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PMID:Polybase induced lysis of yeast spheroplasts. A new gentle method for preparation of vacuoles. 24 1

The gene coding for a thermostable exo-alpha-1,4-glucosidase (alpha-glucoside glucohydrolase: EC 3.2.1.20) of Bacillus stearothermophilus ATCC 12016 was cloned within a 2.8-kb AvaI fragment of DNA using the plasmid pUC19 as a vector and Escherichia coli JM109 as a host. E. coli with the hybrid plasmid accumulated exo-alpha-1,4-glucosidase mainly in the cytoplasm. The level of enzyme production was about sevenfold higher than that observed for B. stearothermophilus. The cloned enzyme coincided absolutely with the B. stearothermophilus enzyme in its relative molecular mass (62,000), isoelectric point (5.0), amino-terminal sequence of 15 residues (Met-Lys-Lys-Thr-Trp-Trp-Lys-Glu-Gly-Val-Ala-Tyr-Gln-Ile-Tyr-), the temperature dependency of its activity and stability, and its antigenic determinants.
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PMID:Cloning and expression of a thermostable exo-alpha-1,4-glucosidase gene from Bacillus stearothermophilus ATCC12016 in Escherichia coli. 136 46

The effect on rats of oral doses (38.66 mM/kg body wt) of propane-1,2-diol (PD) administered daily for 10 (Group 1), 20 (Group 2), and 30 days (Group 3) was investigated. Weight gain was initially retarded (P less than 0.05) in Group 1, but was later reversed and elevated significantly (P less than 0.05) in Groups 2 and 3 as compared with their respective controls receiving an equal volume of saline. PD showed a tendency toward enhancing the activities of various enzymes involved in terminal digestion, with the significant effect exerted in few groups on sucrase (P less than 0.05), lactase (P less than 0.05), and gamma-glutamyl transpeptidase (P less than 0.05) when compared with the respective controls. Absorption of D-glucose, glycine, L-aspartic acid, L-lysine, and calcium was elevated and was especially significant in Groups 2 and 3 (P less than 0.001). The structural integrity of the jejunal surface was retained for the most part. A similar examination of the effects of PD was also carried out in vitro to ascertain whether PD itself or its metabolites are involved in its action. The in vitro effects of propane-1,2-diol were compared with those of the more toxic compound propane-1,3-diol. The former exerted greater inhibitory action on the activities of the disaccharidases. The degree of inhibition was in the order sucrase much greater than lactase greater than maltase. The kinetic data revealed that inhibition by 1,2-diol in native and detergent solubilized sucrase is noncompetitive, with Ki values in the range of 0.35-0.41 M. The two diols did not alter the nutrient transport in the brush border membrane vesicles. The present work on rats indicates that PD may influence the intestinal digestive and absorptive functions in vivo and that this in vivo effect of PD is different from that observed in vitro suggesting that the nutritional and toxicological effect of PD may be mediated by different mechanisms.
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PMID:The effect of propane-diols on the intestinal uptake of nutrients and brush border membrane enzymes in the rat. 188 24

The neutral maltase-glucoamylase complex has been purified to homogeneity from the brush-border membrane of rabbit intestine and kidney. Chemical modification of the amino acid side chains was carried out on the purified enzymes. Studies on the kidney enzyme revealed that tryptophan, histidine and cysteine were essential for both maltase and glucoamylase activities, whereas tryptophan, histidine and lysine were essential for the maltase and glucoamylase activities of the intestinal enzyme. Though there was no difference in the amino acids essential for the hydrolysis of maltose and starch by any one enzyme, starch hydrolysis seems to require two histidine residues instead of the one which is required for maltose hydrolysis. This appears to be true for both the intestinal and kidney enzymes.
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PMID:A comparison of the active site of maltase-glucoamylase from the brush border of rabbit small intestine and kidney by chemical modification studies. 200 4

An experiment was done to determine maltase, sucrase, isomaltase, and trehalase activities in mucosa of different segments of small intestines of young turkeys as influenced by age and diet. Two-day-old poults were fed diets containing no added fat [44.6% starch, 2.2% ether extract by weight (HC)], 10% tallow (T), or 10% corn oil [(CO) 29.0% starch, 10.9% ether extract]. Diets HC, T, and CO were calculated to contain 2,705, 3,083, and 3,196 kcal ME/kg, respectively, and constant protein, TSAA, and lysine:ME ratios were maintained. Appreciable maltase and isomaltase specific activities (micromoles of substrate hydrolyzed per milligram protein per hour) were observed in 2-day-old poults, and activities of these enzymes increased in poults fed the HC diet through 7 and 14 days, respectively. At 2 days, specific activity of sucrase was low, and trehalase activity was not detected. Sucrase activity increased steadily through 28 days of age in poults fed the HC diet. Trehalase activity was detected at 7 days of age and reached a maximum by Day 21 after hatch. By Day 28, trehalase activity had disappeared from all segments except for the proximal jejunum. In 28-day-old poults fed the HC diet, specific activities of all disaccharidases were greatest in the jejunal segments; i.e., 21, 1.06, 7.24, and .034 mumol/mg protein/h for maltase, sucrase, isomaltase, and trehalase, respectively, in the proximal jejunum. Poults fed the T or CO diets had significantly lower disaccharidase activities than did those fed the HC diet, beginning at 7 days of age. Changes in specific activities of disaccharidases as related to age or diet or both were not always parallel, suggesting that each enzyme may be regulated by or affected by diet in a partly independent way.
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PMID:Intestinal disaccharidases of young turkeys: temporal development and influence of diet composition. 264 74

1. In the newborn pig it appears that only prenatally produced enterocytes are capable of absorbing large amounts of protein. 2. The ability of the small intestine to transport sodium, lysine, lysine containing dipeptides and glucose declines markedly during the first week of post natal life. 3. Dexamethosone causes a doubling of the sodium dependent portion of alanine uptake. 4. EGF given between days three and six of postnatal life increases sucrase and maltase activity in the distal region of the small intestine. 5. Weaning induced problems are probably not due to direct inhibition of transport properties.
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PMID:Postnatal development of transport function in the pig intestine. 290 64

A model of nonischemic hypoxia of the jejunum was designed in dogs, by shunting of blood from the inferior vena cava directly into the regional mesenteric arterial supply, thereby lowering the PaO2 of the blood that reached the jejunal wall from 98.6 +/- 3 to 62 +/- 5 mm Hg. Absorption rates of sodium, glucose, fructose, glycine, and the dibasic aminoacid lysine were studied by in situ luminal perfusion of a 30-cm proximal jejunal segment with a bicarbonate buffer solution containing phenol red as a nonabsorbable marker for determination of water fluxes. During periods of control, hypoxia, and after discontinuation of the venoarterial admixture (recovery), effluent perfusate was collected and mucosal biopsies were obtained for assay of lactase, maltase and sucrase activity, mucosal ATPase activity and ATP content, and for light- and electron microscopic examination. Mesenteric supply with hypoxic blood was associated with a significant inhibition of Na+,K+-ATPase activity (p less than 0.001) and a rise in mucosal ATP content (p less than 0.05). There was a significant reduction in the absorption rates of sodium (p less than 0.001), glucose, and glycine (p less than 0.01), but no change in the transport of fructose and of lysine. Brush border enzymes were unaltered. The histological appearance of the mucosa remained normal throughout the experiment, but on electron microscopy a distinct swelling of the enterocyte mitochondria was noted during the hypoxia period.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of nonischemic hypoxia on jejunal mucosal structure and function: study of an experimental model in dogs. 294 46

The s.c. administration of cortisol to hamsters (50 mg/kg body wt/day for 4 days) produces a significant increase in maltase sucrase, alkaline phosphatase and leucineaminopeptidase activity in intestinal mucosa. Lactase activity is unaffected by cortisol. Gamma-glutamyltranspeptidase activity increases slightly in females but remains unchanged in males. Cortisol causes increase in proline and glycine absorption without changing the absorption of lysine.
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PMID:The effect of cortisol on stimulation of enzymatic activity and absorption of amino acids in the small intestine of adult hamsters. 615 Jul 87

In vivo jejunal transport of amino acids, monosaccharides, sodium, and electrolytes were studied in rats made nephrotic with puromycin aminonucleoside (PAN) and in pair-fed controls. Studies were performed 14 days after a single intravenous dose of PAN when rats were no longer edematous, but were still hypoproteinemic. There was decreased absorption of glucose, 3-0-methyl glucose, glycine, phenylalanine, histidine, water, and sodium in the nephrotic animals but transport of fructose, lysine and potassium was similar in the nephrotic and control animals. Enzyme kinetic studies for glucose transport showed a mixed type of inhibition affecting both Vm and Km. The jejunal mucosa of nephrotic and control rats had similar ATP content and enzyme activity for lactase, sucrase, maltase and (Na-K)-ATPase and the ratios of RNA to DNA were similar in the nephrotic and control rats. No abnormality of the jejunum was detected by light or electron microscopy. The data suggest that the impairment of absorption is a result of decreased activity of jejunal membrane carrier mechanisms. The altered transport may be secondary to effects related to the metabolic consequences of nephrotic syndrome and does not appear to be related to acute purine aminonucleoside toxicity, edema or malnutrition.
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PMID:Jejunal transport in experimental nephrotic syndrome. 662 9

The alpha-glucosidase specific for the hydroxylysine-linked disaccharide units of collagens (or 2-0-alpha-D-glucopyranosyl-5-0-beta-D-galactopyranosylhydroxy-L-lysine glucohydrolase) has been measured in kidney cortex and brain cortical tissue of streptozotocin diabetic rats after 19, 23 or 28 weeks of diabetes and of aged rats 22 months old. Increased specific activities of the enzyme have been found repeatedly in the dialyzed homogenates and the 7.2 X 10(6) g.min supernatants of kidney and brain at the various stages of diabetes when compared with age-matched controls; the specific activities returned to a normal level after insulin treatment. Similar increased specific activities were observed in kidney and brain of the aged normoglycemic rats when compared with young adult rats. In diabetic kidney cortex, beta-galactosidase and p-nitrophenyl-alpha-D-glucoside glucosidase specific activities were decreased in contrast to the increase of glucosyl-galactosyl-hydroxy-lysine glucohydrolase. In kidney cortex of the aged rats, beta-galactosidase activity was also decreased, but p-nitrophenyl-alpha-D-glucoside glucosidase was increased. In both diabetic and aged rats, thickening of the kidney glomerular basement membranes was confirmed; thickening of the brain cortical capillary basement membranes was also observed. Thus in the diabetic and aged animals, the increased glucosyl-galactosyl-hydroxylysine glucohydrolase specific activity was associated with basement membrane thickening in the kidney and the brain.
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PMID:Studies on the alpha-glucosidase specific for collagen disaccharide units: variations associated with capillary basement membrane thickening in kidney and brain of diabetic and aged rats. 716 52


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