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)

The effects of sucrose and corticosterone on the expression of intestinal sucrase activity in preweanling rat pups were studied using an artificial rearing (AR) technique. When AR rat pups were isocalorically fed diets containing lactose or sucrose, or a carbohydrate-free diet from d 12-16, jejunal and ileal sucrase and maltase activities were induced to similar levels in all AR rats, whereas ileal lactase activity was precociously decreased. In separate experiments, enzyme activities were measured in ileal isografts subcutaneously implanted in littermates at birth. In AR rats fed the lactose diet, these isografts showed sucrase and maltase activities comparable with those of host ileum and also to isografts from AR rats fed the sucrose diet. In contrast, lactase activity was significantly higher in isografts than host ileum in all AR rats. Serum corticosterone levels were significantly elevated in AR rats for 24 h after intragastric cannular implantation. Precocious expression of ileal sucrase activity occurred in corticosterone treated, but not in untreated, adrenalectomized AR rats. In conclusion, dietary sucrose has no specific role in enhancing intestinal sucrase activity, and endogenous corticosterone is responsible for the induction of sucrase activity in AR rats.
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PMID:Endogenous corticosterone rather than dietary sucrose as a modulator for intestinal sucrase activity in artificially reared rat pups. 352 29

The definition of "insufficient" small bowel lactase activity varies greatly among authors. The present study is aimed at redefining lactase insufficiency by comparing intestinal lactase activity and results of the lactose breath hydrogen test. Primary "insufficient" lactase activity was considered to be present when a child with a normal small bowel histology showed lactose malabsorption as measured by the lactose breath hydrogen test. The lactase activity of 22 "normal" children ranged from 0.77 to 4.57 U/g wet weight, while five children showed primary lactase insufficiency as defined above. Small bowel lactase activity in the latter patients was less than 0.74 U/g wet weight. Sucrase and maltase activities were similar in both groups of patients. We conclude that children with a normal small bowel histology should be considered to have primary lactase insufficiency when small bowel lactase activity is below 0.75 U/g wet weight.
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PMID:Lactase insufficiency revisited. 393 58

The localization of disaccharidases in kidney has been studied by means of the multiple indicator dilution technique. A pulse injection of a solution containing Evans blue dye (plasma marker), creatinine (extracellular marker), and a (14)C-labeled disaccharide (lactose, sucrose, maltose, and alphaalpha-trehalose), is made into the renal artery of an anesthetized dog, and the outflow curves are monitored simultaneously from renal venous and urine effluents. Lactose and sucrose have an extracellular distribution. Trehalose and maltose remain extracellular from the postglomerular circulation. About 75% of filtered tracer maltose or trehalose is extracted by the luminal surface of the nephron. Thin-layer chromatography of urine samples shows that all of the excreted (14)C radiolabel is in the form of the injected disaccharide. Following the administration of phlorizin, all of the filtered radioactivity is recoverable in the urine, but chromatography of the urine samples now reveals that there is a significant excretion of [(14)C]glucose, approximating the amount previously extracted under control conditions (in the absence of phlorizin). It has been verified that no hydrolysis of maltose or trehalose to their constituent glucose subunits occurred during the transit of tracer between the point of injection (renal artery), and the point of filtration (glomerular basement membrane). Similarly, after addition of [(14)C]disaccharides to fresh urine there is no chromatographically recoverable [(14)C]glucose. It is concluded that there exist alpha-glucosidases with maltase and trehalase activity along the brush border of the proximal tubule and that these disaccharidases are located spatially superficial to the glucose transport receptors.
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PMID:Brush border disaccharidases in dog kidney and their spatial relationship to glucose transport receptors. 472 44

Diarrhoea is a common sequel to vagotomy and pyloroplasty but its cause is unknown. One of our patients who developed this complication had an abnormal lactose barium meal and responded well to a lactose-free diet. This led us to make a systematic study of disaccharidase activity in the small intestine in patients with diarrhoea following vagotomy and pyloroplasty. The small-intestinal disaccharidases have been estimated in jejunal biopsy specimens taken from 23 patients suffering from persistent diarrhoea, either continuous or episodic, after vagotomy and pyloroplasty. The disaccharidase values were normal in all but one of these patients. This patient showed hypolactasia but the sucrase and maltase levels were normal. The jejunal biopsy specimen taken from this patient showed a convoluted pattern under the dissecting microscope and severe partial villous atrophy under the light microscope. A repeat jejunal biopsy taken 20 cm beyond the duodeno-jejunal flexure showed similar appearances and also had a low level of lactase. However, two lactose tolerance tests and a lactose barium meal yielded normal results, suggesting that the low level of lactase in the upper jejunum was not a limiting factor in lactose absorption. The finding of one example of a low lactase level among 23 postvagotomy patients corresponds with what is being found in a study of normal subjects at present in progress. In effect, almost all patients with persistent diarrhoea after vagotomy and pyloroplasty have normal small-intestinal disaccharidase activity.
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PMID:Disaccharidase levels in the small intestine in patients with diarrhoea following vagotomy and pyloroplasty. 554 54

The specific effect of dietary sugars on jejunal disaccharidase activity in seven normal nonfasted male volunteers was studied. The sugars tested were sucrose, maltose, lactose, glucose, fructose, and galactose. Comparisons were made of the effects of each sugar in an isocaloric liquid diet. In all subjects, sucrose feeding, as compared to glucose feeding, significantly increased jejunal sucrase (S) and maltase (M) activities, but not lactase (L) activity. The S/L and M/L ratios increased to a significant degree. Fructose feeding, in two subjects, gave results similar to sucrose when comparing fructose and glucose diets. One subject was fed lactose, galactose, and maltose. These sugars, compared to glucose, did not increase disaccharidase activity. Fructose appears to be the active principle in the sucrose molecule. These results demonstrate that specific dietary sugars can alter enzyme activity in the small intestine of man in a specific fashion. Sucrose and fructose are able to regulate sucrase and maltase activity. Dietary alteration of intestinal enzymes may represent a suitable system for studying the regulation of enzyme activity in man.
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PMID:Control of jejunal sucrase and maltase activity by dietary sucrose or fructose in man. A model for the study of enzyme regulation in man. 567 20

1. Disaccharidase activities of the small and large intestines of the chick were studied. 2. Homogenates of the small intestine readily hydrolysed maltose, sucrose and palatinose (6-O-alpha-d-glucopyranosyl-d-fructose), hydrolysed lactose slowly and did not hydrolyse trehalose and cellobiose. 3. Within the small intestine the disaccharidases were located mainly in the intestinal wall; the activity in the contents accounted for less than 5% of the total activity. 4. The disaccharidases were non-uniformly distributed along the small intestine, the activities being greatest in the middle section. 5. The disaccharidase activities increased with age between 1 and 43 days. 6. Homogenates of the large intestine and contents readily hydrolysed maltose, sucrose, palatinose and lactose and hydrolysed cellobiose and trehalose slowly. 7. The large-intestinal disaccharidases were located mainly in the contents. 8. Similar K(m) and pH optimum values were found for the maltase, sucrase and palatinase activities of the large and small intestines. 9. The lactase activity of the large intestine was markedly affected by diet and had different K(m) and pH values from the small intestinal lactase. 10. Low activities of intestinal disaccharidase were found in 12-day-old embryos and marked increases in the intestinal disaccharidases of the developing embryo occurred 2-3 days before hatching.
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PMID:Intestinal disaccharidase activities in the chick. 577 6

The metabolism of circulating disaccharides was studied in adult humans and rats. After iv infusions of 10 g of either lactose, sucrose, or maltose in four adults, no rise in blood glucose was noted. A mean of 8.7+/-1.89 g of the lactose and 6.3+/-1.39 g of the sucrose was excreted in the 24-hour urine sample. Only 0.11+/-0.03 g of the infused maltose was recovered in the urine, suggesting that the maltose was metabolized.After injection of (14)C-labeled lactose and sucrose in rats, 6.2+/-2.7 and 7.6+/-2.4%, respectively, was oxidized to (14)CO(2) in 24 hours; 62.1+/-13.5 and 68.4+/-10.8% of the respective disaccharides was excreted into the urine. Conversely, after injection of (14)C-labeled maltose 54.6+/-7.0% was oxidized to (14)CO(2) and 4.8+/-3.9% excreted in the urine. The per cent of maltose oxidized to CO(2) was similar to that of glucose. In addition to small intestinal mucosa, homogenates of rat kidney, brain, and liver as well as serum were found to have measurable maltase activities. The role of these tissue maltases in the metabolism of circulating maltose and maltosyloligosaccharides is discussed.
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PMID:Metabolism of circulating disaccharides in man and the rat. 602 Dec 3

Giant-cell formation induced by macrophage fusion factor (MFF) was not altered after pretreatment of macrophages with trypsin, chymotrypsin, pronase, neuraminidase, phospholipase C, or phospholipase D. Pretreatment of macrophages with either alpha-mannosidase or alpha-glucosidase completely inhibited giant-cell development, without altering macrophage viability. No alteration of giant-cell formation was observed when 0.1 M of L-fucose, N-acetyl-glucosamine, D-arabinose, D-xylose, melibiose, D-glucose, D-galactose, alpha-lactose, sucrose, D-fructose, or maltose was present during incubation of macrophages with MFF. Giant-cell formation was abolished when 0.1 M alpha-D-mannose was present during macrophage incubation with MFF. These results suggest that the protein moiety of MFF recognizes a specific receptor site on the macrophage membrane, one that is different from those described for other lymphokines and contains alpha-mannose.
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PMID:Chemical nature of the interaction between macrophage fusion factor and macrophage membranes. 635 71

The activities of the disaccharidases lactase, maltase, and sucrase were determined in upper jejunal biopsies of 65 healthy adult German males. The study was an attempt to demonstrate the gene-dosage effect on lactase activity expected from the presence of a "hypolactasia" (l) and a "lactase-persistence" (L) allele in the German population. In contrast to lactase/sucrase ratios, lactose/maltose ratios showed a trimodal distribution in proportions of presumed genotypes LL, Ll, and ll compatible with Hardy-Weinberg equilibrium. The frequency of homozygotes ll (13.8%) was similar to the average frequency of lactose malabsorbers in Germany reported in the literature. The importance of considering the lactase gene-dosage effect in population studies of lactase activity is discussed.
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PMID:Gene-dosage effect on intestinal lactase activity demonstrated in vivo. 642 39

Inhibition of microbial enzymes in human dental plaque catalyzing the cleavage of the disaccharides maltose, sucrose and lactose was carried out with the alpha-glucosidase inhibitor, acarbose. The maltases from plaque homogenates were totally inhibited, whereas the inhibition of the invertases varied considerably. With increasing inhibitor concentrations, from 1 mM to 50 mM, the inhibition of the invertases increased. Preincubation for 30 min of the plaque homogenate with inhibitor resulted in a 20% increase of the inhibition of invertase activity. The inhibitor showed non-competitive inhibition of the invertases in the homogenates, whereas the maltases were competitively inhibited. The lactases were not inhibited at all. The invertases from human dental plaque may be alpha-glucosidases and/or beta-fructosidases.
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PMID:Effect of the alpha-glucosidase inhibitor, acarbose, on disaccharide splitting enzymes in human dental plaque. 680 51


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