Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.26 (invertase)
 4,927 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of a new complex oligosaccharide (Bay g 5421) of microbial origin on human intestinal alpha-glucosidehydrolase activity was tested in mucosal homogenate from human small bowel biopsy specimens. The alpha-glucosidehydrolase inhibitor (alpha-GHI) exerted a potent inhibitory effect on glucoamylase, sucrase, and maltase, was minimally effective on isomaltase, and did not affect trehalase and lactase activity. Kinetic analysis revealed a fully competitive type of inhibition with a Ki of 1.3 x 10(-6) M; thus the inhibitor had a 15,000-fold higher affinity to the enzyme sucrase than its natural substrate sucrose. The new compound may prove to be useful in the study of carbohydrate maldigestion and malabsorption and may possibly be of therapeutic benefit in diabetes and obesity.
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PMID:Inhibition of human intestinal alpha-glucosidehydrolases by a new complex oligosaccharide. 44 22

Gluten withdrawal from the diet is occasionally used speculatively in the management of multiple sclerosis. To assess whether there might be any rational basis for such a measure we have undertaken morphological and biochemical studies of the jejunal mucosa in 14 patients with multiple sclerosis. All were found to have morphologically normal villi, and quantitative estimation of surface-to-volume ratios gave values which did not differ from control subjects. Intraepithelial lymphocyte counts were normal. Antigliadin antibody titres were not raised in any patient. Estimation of activity of the brush border disaccharidases (sucrase, lactase, and maltase (showed that the mean level of each enzyme did not differ significantly from control subjects. Analytical subcellular fractionation of the biopsies showed no changes in the distribution or activity of marker enzymes for the brush order, lysosomes, mitochondria, cytosol, peroxisomes, or endoplasmic reticulum. It is concluded that there are no gross morphological or biochemical abnormalities in the jejunal mucosa in patients with multiple sclerosis and, therefore, that the use of gluten-free diets cannot be justified on the assumption that these patients suffer from a coeliac-like lesion of the small intestine.
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PMID:Morphological and biochemical findings in jejunal biopsies from patients with multiple sclerosis. 44 78

Brush border sucrase and alkaline phosphatase activities are considerably enhanced in the intestine of ascorbic acid deficient guinea-pigs. Similar increase in the uptake of D-glucose and L-alanine also occurs in chronic vitamin C deficiency. However the permeability of D-glucose and L-alanine in the intestine of animals fed with large doses of vitamin C is severely depressed, with a reduction in the levels of sucrase and alkaline phosphatase activities.
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PMID:Effect of chronic hypo and hypervitaminosis C on the brush border enzymes and the intestinal uptake of glucose and alanine. 47 73

Jejunal mucosal function and structure was examined in 31 patients with ulcerative colitis and 29 patients with Crohn's disease with ileal, ileocolonic or colonic involvement; A significant reduction of the specific activity of disaccharidases (lactase, sucrase and trehalase) in jejunal mucosal homogenate occurred in patients with inflammatory bowel disease. Similarly, alkaline phosphatase was reduced in ulcerative colitis. Several dipeptidases such as glycyl-leucine, leucyl-glycine, glycyl-glycine and valyl-proline hydrolase activities were lower in patients with inflammatory bowel disease than in controls. Histological changes in jejunal mucosal biopsies occurred in 71% of patients with ulcerative colitis and 61% with Crohn's disease. These changes ranged from mild abnormalities of villus architecture to marked reduction of villus height. Most patients with a reduction in mucosal enzymes had concommitant morphological changes in jejunal mucosal biopsy. The results of this study indicate that functional and structural abnormalities of the jejunal mucosa frequently occur in patients with inflammatory bowel disease without radiologic evidence of proximal small bowel involvement.
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PMID:Abnormalities of jejunal mucosal enzymes in ulcerative colitis and Crohn's disease. 47 7

To identify the site of stimulation of sucrase by a sucrose diet, changes in sucrase-specific activity of jejunal mucosa were studied after introduction of sucrose diet to carbohydrate-deprived rats. Results were correlated with simultaneous changes in villus gradients of sucrase-specific activity. Simultaneous with the introduction of sucrose diet, [(3)H]thymidine (100 muCi) was administered intravenously, and rates of cell migration measured during adaptation to the new diet. After a 72-h fast, rats fed sucrose diet for 6, 12, or 18 h showed no change in sucrase-specific activity in either whole mucosa or villus gradients. However, within 18-24 h after starting a sucrose diet, there was a marked rise in whole mucosal sucrase-specific activity above fasting values (99 +/- 14 vs. 38 +/- 4 muM glucose/min per g protein, P < 0.001) in association with the development of a region of increased activity at the lower villus (154 +/- 22 vs. 60 +/- 9 muM glucose/min per g protein, P < 0.02, but with no change in villus tip activity (56 +/- 5 vs. 46 +/- 8 muM glucose/min per g protein). Similar changes were seen in animals fed 24 h of sucrose diet after a 72-h carbohydratefree diet. Fasted animals fed sucrose diet for 36 h had increased sucrase-specific activity at the villus tip (144 +/- 11 muM glucose/min per g protein) as well as at the lower villus region, and this pattern persisted at 1 wk of sucrose diet. Maximal activity patterns for isomaltase and maltase paralleled those for sucrase, but the villus gradients for lactase were unaffected by sucrose diet. The region of maximal sucrase-specific activity always coincided with or followed the leading edge of radioactivity as determined by liquid scintillation counting. Therefore, sucrose-mediated changes in sucrase activity of the jejunal mucosa in the rat appear to be initiated at the level of the crypt epithelial cell and are expressed after a latent period of 18-24 h during which these cells mature and migrate toward the villus tip.
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PMID:Site of substrate stimulation of jejunal sucrase in the rat. 47 72

The roles of extracellular and intracellular mechanisms in the degradation of brush border proteins have been investigated by studying the small intestinal mucosa of dogs with naturally occurring exocrine pancreatic insufficiency. Peroral jejunal biopsies were homogenised and the organelles separated by isopycnic centrifugation on continuous sucrose density gradients. The distributions of marker enzymes for the principal subcellular organelles were determined in the gradients and related to the specific activities in the homogenates. There were increased activities of the brush border carbohydrases zinc-resistant alpha-glucosidase, maltase and sucrase in the pancreatic insufficient animals, but no change in lactase activity. The activity of gamma-glutamyl transferase was also higher in the affected group; the activities of two other brush border enzymes, alkaline phosphatase and leucyl-beta-naphthylamidase, however, were unaltered. These findings with an increase in the modal density of the brush border from 1.20 to 1.22 are consistent with an enhanced glycoprotein content of the microvillus membrane. There were also rises in the activities of lysosomal enzymes. N-Acetyl-beta-glucosaminidase activity was increased in the soluble fractions and the percentage latent enzyme activity was reduced, findings indicative of an increased fragility of the lysosomal membrane. There were no marked alterations in the activities or density gradient distributions of marker enzymes for the other organelles, stressing the specificity of the changes in the brush borders and lysosomes. These findings are compatible with the degradation of certain exposed brush border proteins by pancreatic proteases and suggest that when this is defective, intracellular degradative mechanisms may be stimulated.
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PMID:Biochemical changes in the jejunal mucosa of dogs with naturally occurring exocrine pancreatic insufficiency. 48 65

In order to investigate the relationship between dietary amino acids and protein, and activities of intestinal sucrase [EC 3.2.1.26] and leucine aminopeptidase [EC 3.4.11.1, LAPase] in rats, the effect of supplementation of amino acids into a protein-free diet and a low casein diet containing sucrose as the carbohydrate source on these enzyme activities was studied. The segmental weights of the small intestine and its mucosa of rats fed the protein-free diet supplemented with L-methionine or with L-methionine and L-threonine at 0.1 or 0.2% levels were significantly higher than those of rats fed the protein-free diet or one supplemented with L-glutamic acid, but there was no difference in the segmental activities of the sucrase and LAPase among rats fed these diets. On the other hand, the supplementation of methionine or methionine plus threonine to the 5% or 10% casein diet produced remarkable increases in the segmental weights of the small intestine and its mucosa as well as in the segmental activities of the sucrase and LAPase. There was no difference between the segmental sucrase activity of rats fed the 10% casein diet supplemented with 0.2% methionine ad libitum and that of rats fed this diet under restricted feeding conditions, although the segmental LAPase activity was affected by the amount of food consumed.
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PMID:Effect of diets supplemented with amino acids on intestinal sucrase and leucine aminopeptidase activities in rats. 50 50

Intestinal metaplasia in human stomach was distinguished macroscopically into sucrase-positive and trehalase-positive areas, and sucrase-positive and trehalase-negative areas, by location of these disaccharidase activities with TES-Tape. After location of these two areas with TES-Tape, tissues were taken from them for colorimetric measurement of sucrase, trehalase, leucine aminopeptidase (LAP), and alkaline phosphatase (ALP). Results showed that in the mucosa from sucrase-positive and trehalase-negative areas, trehalase activity was not detectable and the activities of sucrase, LAP, and ALP were lower than in sucrase-positive and trehalase-positive areas.
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PMID:Quantitative measurement of intestinal marker enzymes in intestinal metaplasia from human stomach with cancer. 51 Aug 49

The [3H] phlorizin-binding component of brush border vesicles was enriched in situ by negative purification. Several procedures, known to effect selective solubilization of membrane components, were used separately or in combination to remove proteins unrelated to the binding. Deoxycholate ruptured the vesicles and released 67% of their protein, thereby increasing the specific [3H] phlorizin-binding activity of the pellet three-to fourfold. Extracting the deoxycholate-pellets with either NaI or alkaline solutions released up to 38% of the deoxycholate-insoluble protein without significantly affecting phlorizin binding. The polypeptide composition of the membranes at the different stages was analyzed by NaDodSO4-polyacrylamide gel electrophoresis. A number of polypeptides present in the original vesicles could be ruled out as essential components of the [3H] phlorizin binding entity. Intact and deoxycholate-treated vesicles were subjected to proteolytic attack. Papain liberated sucrase and isomaltase from intact vesicles, but affected neither other Coomassie-stained bands nor phlorizin binding. Neither the protein composition nor the binding properties of sealed vesicles were influenced by trypsin or chymotrypsin. However, all the proteolytic enzymes tested on deoxycholate-treated membranes substantially reduced [3H] phlorizin binding and produced concomitantly the disappearance of several bands from the electrophoretic profile. Pretreatment of vesicles with papain, followed by deoxycholate extraction and incubation in alkaline media, increased the specific binding activity of the membranes up to ninefold by removing close to 90% of the protein. A limited number of polypeptides are suggested as possible candidates for the glycoside-binding site of intestinal brush borders.
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PMID:Partial purification of the sugar carrier of intestinal brush border membranes. Enrichment of the phlorizin-binding component by selective extractions. 52 29

A 10-year-old boy with severe familial lactose intolerance in infancy (vomiting, failure to thrive, lactosuria (5.25 g/l), sucrosuria (12 g/l), and aminoaciduria. Intestinal disaccharidases (including lactase and sucrase) normal at age 6 and 20 weeks. Oral lactose tolerance test at this age resulted in lactosuria (4.6 g/l); sucrose tolerance test, in sucrosuria (18.5 g/l). In contrast, intraduodenal lactose tolerance test gave only low lactose excretion in urine (0.28 g/l). He improved rapidly and had no lactosuria on intraduodenal feeding with citric acid milk. The lactosuria diminished as age increased, but was still higher at age 6 years than that of controls. He tolerated normal disaccharide containing food after 1.5 years of age. At 5.5 to 6 years, he had symptoms of lactose malabsorption, and an isolated lactase deficiency was proved. At 10 years, he still tolerates only limited amounts of milk. The defect in severe familial infantile lactose intolerance seems to be localized in the gastric mucosa. Acquired lactase deficiency can appear later in childhood in this syndrome.
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PMID:A boy with severe infantile gastrogen lactose intolerance and acquired lactase deficiency. 52 43


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