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)

Activities of maltase, sucrase, lactase and acid-beta-galactosidase were studied in jejunum and ileum of term rat fetuses obtained by cesarian section. Female rats were either untreated or injected daily in the last (3rd) week of pregnancy with cortisone acetate (10 or 50 mg/100 g body weight) or L-triiodothyronine (20 or 50 microgram/100 g body weight). Two other control groups were injected with appropriate solvents. Cortisone or T3 treatment to mothers increased sucrase and maltase activity in jejunum and ileum of the offspring. Generally, higher doses of hormone were more effective. Lactase activity was increased by 25% in the jejunum by the higher dose of cortisone. Both doses of cortisone increased ileal lactase. Jejunal acid-beta-galactosidase activity was decreased in fetuses of T3-treated mothers.
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PMID:Effect of cortisone or L-triiodothyronine administration to pregnant rats on the activity of fetal intestinal disaccharidases and lysosomal acid beta-galactosidase. 41 95

The changes with age of intestinal mucosa, protein, lactase, maltase and sucrase were followed in the piglet between day 105 of gestation and 8 weeks after birth. Lactase and maltase activities appeared during fetal life in the whole of the small intestine. Activity of sucrase was recorded after the 1st postnatal week. Lactase activity was high at birth and reached a maximum at 1 week (X 2.5); maltase activity which was low at birth increased to the 8th week (X 143). Activities of all enzymes were low in the duodenum; lactase was most active in the jejumum. Similar activities of maltase and sucrase were found in the two distal parts of the small intestine. Specific activity (related to protein content) of lactase reached a maximum at the end of the 1st week after birth and decreased afterwards. Specific maltase and sucrase activities were higher in the 2nd week, decreased between the 2nd and 4th week and increased afterwards (maltase) or decreased to the 6th--8th week (sucrase).
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PMID:Development of digestive enzymes in the piglet from birth to 8 weeks. II. Intestine and intestinal disaccharidases. 41 3

The circadian rhythms in the activities of maltase and lactase of the small intestine were examined at various stages of postnatal development in rats. When the rats were fed ad libitum, no circadian change in the enzyme activities was found during the suckling period or the weaning period. However, several days after the time of weaning, the enzymes showed the same circadian changes as in adult rats with higher activities at night. After weaning, when the rats were fed only during the daytime, the phase of the enzyme rhythm shifted about half a day, and the highest activity was observed around feeding time. However, during the suckling period, no circadian rhythm in the enzyme acvities was found, even when the rats were allowed to feed only during a restricted time of the day.
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PMID:Postnatal development of circadian rhythms in disaccharidase activities in rat small intestine. 41 37

The intestinal brush border disaccharidases separated by gel electrophoresis were studied after oral administration of a high sucrose or lactose diet to 11-day-old suckling rats during 3 days. Some modifications of the brush border protein and eyzyme patterns could be attributed to the effect of the basic diet: increase of glucoamylase, appearance of a weak sucrase activity and of a second molecular form of maltase. However, the specific action of a given disaccharide on the synthesis of the corresponding hydrolytic enzyme could be clearly demonstrated. Indeed, the electrophoretic pattern after sucrose or lactose feeding showed a marked increase of the protein bands corresponding to sucrase-isomaltase or lactase activities.
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PMID:Sucrase and lactase synthesis in suckling rat intestine in response to substrate administration. 41 23

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

Turnover in organ culture of human small intestinal membrane glycoproteins was measured by the pulse-chase technique, using 14C-glucosamine, 14C-fucose or 14C-leucine as tracers. Apparently, low degradation rates were found for the major high-molecular-weight proteins which co-migrated on SDS-polyacrylamide gels with maltase-glucoamylase, lactase-phlorizin-hydrolase and sucrase-isomaltase enzymic activities. In contrast, an unidentified glycoprotein appearing on gels next to alkaline phosphatase exhibited a higher degradation rate with an apparent half-life of about 30 h, this being similar to the half-life of total glycoprotein as measured in mucosal homogenates. The results obtained with the pulse-chase technique were confirmed by double isotope experiments using 14C-leucine and 3H-leucine as tracers. These findings indicate that in organ culture there is a low basic turnover of human intestinal membrane glycoproteins which co-migrate on gels with known glycosidase enzymic activities.
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PMID:Turnover studies of human intestinal brush border membrane glycoproteins in organ culture. 45 41

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

The concomitant appearance of enterokinase (EK) and trypsin activities in the human intestinal mucosa is indicative of the importance of EK as an activator of trypsinogen and therefore as the key enzyme in protein digestion. Enterokinase can be detected in fetal mucosa from the 26th week of gestation on, paralleling appearance of tryptic activity in meconium. The developmental pattern of EK activity increases with age. Between 26 to 30 weeks of gestation, the EK activity is only 6% and full term babies (40 weeks) 20% of that found in older children. In contrast, lactase studies during development show a lactase activity of only 30% in human fetuses between 26 to 34 weeks of gestation as compared to full term babies. During the same gestational period, sucrase and maltase activities reach 70% of the full term. In addition, the distributional pattern of EK differs from the disaccharidases, showing the highest activity in duodenum and the lowest in ileum, whereas disaccharidases are highest in jejunum with lower activity in duodenum and ileum. Differences in topographical distribution and time of appearance of EK and disaccharidases may be attributed to differences in orgin as well as subcellular localization of these enzymes. It is conceivable that the premature infant, between 26 to 30 weeks of gestation, is better equipped to deal with hydrolysis of alpha-glucosides than of lactose.
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PMID:Developmental pattern of small intestinal enterokinase and disaccharidase activities in the human fetus. 55 25


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