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:3.2.1.26 (invertase)
4,927 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Microscopical studies showed that initial differentiation of the guinea-pig small intestine occurs between days 35 and 55 of foetal development. Changes observed at this time include formation of villi (by day 42), elaboration of submucosal duodenal Brunner's glands (by day 49) and the appearance of a well-developed microvillus membrane (by day 56). Different microvillus membrane-associated hydrolases appear at different stages of foetal and postnatal development. The 'early' enzymes such as aminopeptidase, alkaline phosphatase and sucrase show a sharp increase and reach their maximal levels between days 35 and 50, whereas the late enzymes such as dipeptidyl peptidase IV and lactase increase gradually between days 35 and 50, and reach maximal activity between days 50 and 60. A combination of techniques involving precipitation with Mg2+ followed by fractionation on sucrose density gradients has enabled us to prepare, for the first time, a 21-fold enriched microvillus membrane fraction from the foetal intestine. Polypeptide analysis of this membrane fraction by sodium dodecyl sulphate/polyacrylamide gel electrophoresis showed the presence of developmentally specific polypeptides at different stages of foetal and postnatal development. Three polypeptides of molecular weights 205 000, 80 000 and 47 000 are major microvillus membrane components at the 40-day foetal stage. Two other polypeptides of molecular weights 60 000 and 131 000 are major microvillar components at 56-day and older foetal stages as well as at the 3-day neonatal stage. The adult microvillus membrane contained 112 000 and 122 000 Mr polypeptides as major components. The above results were confirmed using two-dimensional isoelectric focussing-sodium dodecyl sulphate/polyacrylamide gel electrophoretic techniques.
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PMID:Structural and biochemical differentiation of the mammalian small intestine during foetal development. 653 51

The gastric- and intestinal-type properties of 15 human gastric cancers, which were transplanted into nude mice, were studied biochemically and histologically. Enzyme activities were determined in the crude extracts of cancer tissues: pepsinogen isozymes as gastric marker enzymes; and sucrase, aminopeptidase (microsomal), and alkaline phosphatase as intestinal marker enzymes. By hematoxylin and eosin staining and paradoxical concanavalin A staining, gastric cancer tissues were classified into gastric type (pyloric gland cell type and surface mucous cell type) and intestinal type (goblet cell type and intestinal absorptive cell type). On the basis of their properties, human gastric cancers were classified into four types: (a) intestinal type; (b) gastric type; (c) intestinal plus gastric type; and (d) unclassified type, showing no gastric- or intestinal-type properties. Of six well-differentiated adenocarcinomas, four were of intestinal type, one of gastric type, and one of intestinal plus gastric type. All of the intestinal-type carcinomas showed sucrase activity. Of the three signet ring cell carcinomas, one was classified as a gastric type, one as an intestinal plus gastric type, and one as an unclassified type. Of the six poorly differentiated adenocarcinomas, five were of the intestinal type and one of the unclassified type. The present results clearly showed the appearance of intestinal-type properties in gastric cancer cells not only in so-called intestinal-type carcinomas, but also in diffuse-type carcinomas.
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PMID:Gastric- and intestinal-type properties of human gastric cancers transplanted into nude mice. 669 75

The present study is concerned with a multilevel approach to human colon organogenesis, involving scanning and transmission electron microscopy together with brush border enzymology. The results emphasize the particular developmental pattern of sucrase activity which appears towards 11 weeks, increases at 14 weeks, begins to decrease around 28 weeks and disappears totally at term. In contrast, other enzymes like aminopeptidase and alkaline phosphatase persist in the adult colon. The correlation, in the fetal large bowel, of enzyme activities and villus structures similar to those found in the small intestine is discussed.
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PMID:Developmental pattern of brush border enzymes in the human fetal colon. Correlation with some morphogenetic events. 671 37

Jejunum of 19-day fetal rats was explanted in organ culture for 48 h in the presence of dexamethasone (DX) and cycloheximide (CX) or actinomycin D (Act D). The concentrations of both inhibitors which provided maximal responses without any detrimental alteration of the tissue were determined. During the culture period, CX (0.5 microgram/ml) totally abolished the production of both DX-stimulated enzymes (sucrase, maltase, lactase) and DX-insensitive enzymes (aminopeptidase, alkaline phosphatase). On the contrary, Act D at 2 micrograms/ml exhibited differential levels of inhibition related to the enzyme considered: 100% for sucrase and aminopeptidase, 70% for maltase and 50% for lactase. By contrast, alkaline phosphatase was stimulated 100% by Act D. These data suggest that the mechanism by which DX induces sucrase and stimulates maltase activity takes place at the transcriptional level. They also indicate that the basic maturation of at least maltase and lactase activities depends upon the traduction of a preexisting pool of mRNAs. The superinduced alkaline phosphatase activity obtained with Act D supports the notion that an Act D-sensitive repressor may play a role in the maturation process of this enzyme.
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PMID:Organ culture of fetal rat intestine. Effects on brush border enzyme activities of the combined administration of dexamethasone and cycloheximide or actinomycin D. 672 12

Jejunal mucosa of 6 d-old rats were cultured for 24 and 48 h in the presence of thyroxine, insulin, pentagastrin, glucagon, epidermal growth factor (EGF) or dibutyryl-A-3:5-MP cyclic with or without dexamethasone (DX). The enzymes were assayed on the purified brush borders. The various agents added alone to the basic culture medium had no effect with the exception of DX on the levels of enzyme activities. Dexamethasone alone induced sucrase, stimulated maltase, and protected other brush border enzyme activities (aminopeptidase, lactase, and alkaline phosphatase). When added to DX-supplemented medium, only the following factors modified the levels of enzymatic activities observed with DX alone. Insulin (10(-6) M) increased maltase, alkaline phosphatase, and lactase activity to a greater extent than DX at 24 h culture, the effect being maintained at 48 h on alkaline phosphatase only. At 48 h culture, both EGF (10(-8) M) and dbcAMP (10(-3) M) decreased DX-induced sucrase activity. The latter agent also depressed DX-stimulated aminopeptidase activity.
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PMID:Organ culture of suckling rat intestine: comparative study of various hormones on brush border enzymes. 674 50

In order to gain more insight into the adaptative mechanism of intestinal enzymes to dietary factors in rats, modifications in the activities of disaccharidases and aminopeptidase were measured after refeeding of a 70% solution of sucrose for 15 h following a 2-day fast. Mature epithelial cells from the villus and immature cells from the crypt were isolated after sequential removal of the cells along the villus-crypt axis. Synthesis of brush border disaccharidases was determined by measuring [3H]valine incorporation into proteins. 1. In the whole mucosa, a highly significant increase in sucrase and maltase activities and a significant drop in aminopeptidase activity was observed in the brush border membranes after sucrose refeeding. 2. Stimulation of sucrase and maltase activities in sucrose refed rats was produced mainly in the immature cells of the crypt and lower villus compartment. 3. After separation of the brush border proteins by SDS gel electrophoresis from villus and crypt cells of sucrose refed rats, major incorporation of the radioactive precursor occured in the protein bands corresponding to sucrase and maltase activities of the lower villus and crypt cell brush borders. These findings demonstrate that sucrase stimulation by sucrose occurs mainly in the immature epithelial cells and that the substrate induces de novo synthesis of sucrase molecules.
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PMID:Effect of sucrose refeeding on disaccharidase and aminopeptidase activities of intestinal villus and crypt cells in adult rats. Evidence for a sucrose-dependent induction of sucrase in the crypt cells. 677 Sep 8

The effects of prolonged alcohol administration were studied on the brush border enzyme activities of the jejunum in rats receiving either a normal laboratory diet or a high carbohydrate-low protein for several weeks. Alcohol (15%) given in association with the normal diet provoked a stimulation of sucrase, maltase, and lactase activities after four weeks, but no significant modification in aminopeptidase activity. These results obtained for the disaccharidases were very similar to those observed with the high carbohydrate-low protein diet given without alcohol, although major differences were obvious in the timing of enzyme stimulation. In contrast, this dietary condition initiated a drop in aminopeptidase activity. When alcohol was given in association with the high carbohydrate-low protein diet, no modification in aminopeptidase activity was detected and the stimulation for the disaccharidase activities was similar to that observed with the high carbohydrate-low protein diet given alone. The present results suggest that the mechanisms involved in the stimulation of brush border disaccharidase activities were different for alcohol and for the high carbohydrate-low protein diet.
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PMID:Effects of prolonged alcohol administration and a high carbohydrate-low protein diet on the activities of the jejunal brush border enzymes in the rat. 681 99

The effect of dexamethasone (DX) on the prenatal maturation of rat intestinal brush border enzymes was studied in organ culture. Jejunal segments were explanted daily from day 17 of gestation until birth, as well as at different postnatal stages until day 6; they were cultured for 48 h with or without DX (8 X 10(-8) M). Enzymatic activities were analyzed on brush border membranes purified from cultured intestines and were compared with values from uncultured specimens. The results showed that DX elicited (a) a precocious induction of sucrase activity in the jejunum explanted from 19 days of gestation onward, reaching a peak value when taken at birth; (b) a stimulation of maltase activity in the segments explanted as soon as day 18, leading to maximal values when taken at day 20, the stage at which the stimulated activity reached a 6.5-fold increase over the baseline activity; and (c) an increase of lactase activity comparable to that occurring in utero. As opposed to this, DX has no specific action on alkaline phosphatase and aminopeptidase activities. The present data indicate that glucocorticoids directly and specifically influence the prenatal maturation of some brush border enzymes in the mammalian gut.
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PMID:Control of brush border enzymes by dexamethasone in the fetal rat intestine cultured in vitro. 682 Nov 11

Amylase, alpha- and beta-glucosidase, alpha- and beta-galactosidase, beta-fructosidase, trypsin, aminotripeptidase, leucine-aminopeptidase, prolinase, prolidase glycyl-L-leucine dipeptidase and glygylglycine dipeptidase are present in the 3rd instar larvae of Chilo auricilius.
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PMID:Digestive enzymes in the gut and salivary gland of the larvae of Chilo auricilius Ddgn. 698 21

The activities of microvillus aminopeptidase (microsomal, EC 3.4.11.2), dipeptidyl peptidase IV (EC 3.4.14.-), glycyl-leucine dipeptidase (EC 3.4.13.11), proline dipeptidase (EC 3.4.13.9), sucrase (EC 3.2.1.48) and gamma-glutamyl transpeptidase (EC 2.3.2.2) were measured in peroral intestinal biopsies taken from patients with coeliac disease in the acute phase and in remission. A comparison with the amounts of corresponding activities from a reference group showed that all the measured activities were significantly decreased in the acute phase of the disease. In patients in remission only microvillus aminopeptidase and dipeptidyl dipeptidase IV displayed a substantial depression as compared to the reference group. It is suggested that a primary mucosal digestion defect will result in lack of substrate for other intestinal enzymes. This is a situation comparable to starvation and may explain the variation in the grade of restitution for the different enzymes.
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PMID:Intestinal peptidases and sucrase in coeliac disease. 700 82


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