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)

High doses of 16,16-dimethyl prostaglandin E2 (dmPGE) are trophic to the small bowel of adult and suckling rats. In suckling rats this effect is paralleled by an increase in brush border enzyme activities, possibly indicating accelerated mucosal maturation. To investigate the possible physiological significance of this phenomenon, we examined whether this induction of intestinal enzyme activities can be reproduced in adult rats and whether cell growth and enzyme activity might be suppressed by indomethacin. Treatment twice daily for 2 weeks with 100 micrograms/kg dmPGE by intragastric instillation increased villus length in the proximal and distal small bowel by 36% and 40%, respectively, while 2 mg/kg indomethacin by subcutaneous injection had no effect. Maltase, trehalase, lactase, and sucrase activities were unchanged after dmPGE or indomethacin. [3H]-thymidine incorporation into DNA was not significantly influenced for up to 24 h after a single dose of both 100 micrograms/kg PGE intragastrically or 10 mg/kg indomethacin subcutaneously. These studies confirm that in adult rats large doses of 16,16-dm PGE2 increase the volume of the small-bowel mucosa. In contrast to the situation in suckling rats, the activity of hydrolytic brush border enzymes is not increased. There is thus no evidence that endogenous prostaglandins are trophic or influence brush border enzymes in the adult rat.
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PMID:Influence of 16,16-dimethyl prostaglandin E2 on morphology and brush border enzymes of small-bowel mucosa. Differences in reactivity between adult and suckling rats. 392 42

Oral (p.o.) administration of a single dose of kalmegh leaf extract (KE; 0.5 g/kg and 1.0 g/kg) or andrographolide (A; 5 mg/kg and 10 mg/kg) to adult male albino rats (100-120 g) produced a dose-related and time-dependent characteristic activation of brush-border membrane-bound hydrolases, viz. lactase, maltase and sucrase in three regions of small intestine (viz. duodenum, jejunum and ileum). The maximum stimulation of these disaccharidases was obtained at 6 hr of either KE or A administration. Further, it was also noted that the extent of activation of the disaccharidases with KE or A, both at higher and lower doses, followed the order: (a) Maltase greater than sucrase greater than lactase in duodenum and (b) Maltase greater than lactase greater than sucrase in jejunum and ileum. Long term administration (for 7, 15 and 30 consecutive days) of either KE (500 p.o.) or A (5 mg/kg/day; p.o.) stimulated lactase, maltase and sucrase in all parts of the small intestine. Maximum stimulation of lactase and maltase was noted after 30 consecutive days of treatment while sucrase exhibited maximum activation after 15 consecutive of treatment with either KE or A. These results suggest that both KE and A accelerate intestinal digestion and absorption of carbohydrate by activating these intestinal disaccharidases.
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PMID:Andrographolide and kalmegh (Andrographis paniculata) extract: effect on intestinal brush-border membrane-bound hydrolases. 393 7

The changes of the transmural electrical potential difference (delta PD) evoked by infusion of glucose, maltose and sucrose and the disaccharidase activities in the everted intestine were studied in diabetic rats. After the induction of diabetes by streptozotocin, delta PDs evoked by sugars and the enzyme activities were observed in the jejunum and ileum. delta PDs evoked by glucose, maltose and sucrose markedly increased both in the jejunum and ileum of diabetic rats. The Kt values for these sugars in diabetic rats were the same as those of control rats. The Vmax values were significantly increased in the ileum of diabetic rats. Maltase and sucrase activities in the ileum increased in diabetic rats. Highly significant linear correlations were found between the delta PDs evoked by glucose and the delta PDs evoked by maltose or sucrose both in the jejunum and ileum of control and diabetic rats. However, delta PDs evoked by maltose and sucrose did not correlate with maltase and sucrase activities in the jejunum. In the ileum, delta PDs evoked by sucrose correlated with the sucrase activity which was very low. These results suggest that the increase of transport of glucose derived from disaccharides in the diabetes induced by streptozotocin is mainly due to the increased activity of the glucose transport system, but not due to the increase of disaccharidase activities.
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PMID:Changes of sugar-evoked transmural potential differences in intestine of rats with streptozotocin-induced diabetes. 406 65

A technique for the isolation of intact brush borders from rabbit renal cortex was evaluated. The procedure was monitored by phase and electron microscopy and marker enzymes, i.e. ATP:NMN adenylyl transferase, nuclear; cytochrome oxidase, mitochondrial; beta-glucuronidase, lysosomal; and glucose-6-Pase, microsomal; and indicated an essentially pure preparation of brush borders. The disaccharidase, trehalase, previously reported in renal tubules, was localized uniquely in brush borders. Maltase was also found; the specific activities of the two enzymes in the brush borders were increased 10- to 20-fold. Other disaccharidases, such as sucrase, isomaltase, lactase, and cellobiase, were absent. It is suggested that trehalase and maltase are appropriate candidates for marker enzymes of the renal brush border. Isolated brush borders possessed a ouabain-sensitive (Na(+) + K(+)) ATPase, an oligomycin-insensitive Mg(++) ATPase, and a Ca(++)-activated ATPase. Alkaline phosphatases, dephosphorylating beta-glycero-P, and trehalose-6-P were also present. The specific activities of these enzymes were increased three-to-five fold in the brush-border preparations; however, activities were found in other subcellular fractions of the renal cortex. Hexokinase, although evident in the isolated brush border, was found prominently associated with other membranous fractions. Phosphoglucomutase and UDPG pyrophosphorylase were localized in the soluble fraction of the renal cortex.
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PMID:Isolation and biochemical characterization of brush borders from rabbit kidney. 425 Jun 12

Mutant strains of Neurospora crassa that lack trehalase and are unable to grow on trehalose were isolated, and the gene (tre) was positioned on the right arm of linkage group I. Maltase and beta-galactosidase activities are almost identical in tre(-) strains, whereas that of invertase was reduced by more than half and those of acid phosphatase and amylase were somewhat increased. Heterocaryons between standard and trehalaseless strains yield less than one-tenth the activity of the former. In addition, strains with duplications heterozygous for trehalase produce less than 1% of the activity of the standard strain. An inhibitor of trehalase has been found in tre(-) strains; its sensitivity to heat and proteolysis, and its nondialyzability suggest that this substance is a protein. The mig gene, which determines the rate of migration of trehalase on acrylamide gels, has been shown to be less than 1 map unit away from the tre gene.
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PMID:Isolation, mapping, and characterization of trehalaseless mutants of Neurospora crassa. 500 Dec 11

The activities of intestinal sucrase and isomaltase are not detectable in rats before 15-16 days of age, but administration of corticosteroids precociously induces the activities of these two alpha-glucosidases. 9-day old rats were removed from their mothers, warmed in an incubator, and fed by constant infusion through gastrostomies. The basic diet was a soya preparation to which various sugars were added. When the diet contained 2% sucrose, diarrhea ensued for 48 hr, but subsided when intestinal sucrase and isomaltase appeared precociously. In animals fed sucrose, the activities of sucrase and isomaltase were markedly increased as compared to animals on carbohydrate-free diets (sucrase 2.41+/-0.23 vs. 0.63+/-0.13 U, isomaltase 3.43+/-0.42 vs. 0.78+/-0.18 U). Maltase activity was doubled, while lactase was not altered significantly. The mitotic index of crypt cells, the depth of crypts, and incorporation of thymidine-(3)H into DNA were increased. In adrenalectomized rats, activities of sucrase and isomaltase were not detected nor induced by sucrose. Steroids given to adrenalectomized rats caused appearance of the enzymes; but if cortisone and sucrose were given together, there was synergism evidenced by a marked increase in activities (sucrase 7.2+/-1.1 vs. 0.68+/-0.12 U). In contrast to observations in adult animals, the effect of sucrose on alpha-glucosidases in developing animals demands the participation of the adrenal gland.
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PMID:Effect of carbohydrate and corticosteroids on activity of -glucosidases in intestine of the infant rat. 505 29

1. An account is given of the absorption of disaccharides by the small intestine of Rana temporaria, R. pipiens and Bufo vulgaris perfused in vitro through the vascular system. Maltase and trehalase activity are found in the intestine of all three species; very small amounts of sucrase are present in the intestine of R. pipiens but there is no evidence for the presence of lactase in any of the animals studied.2. During maltose absorption free glucose appears in the vascular effluent and in the intestinal lumen. Only very small quantities of disaccharide are found in the vascular effluent. The concentration of free glucose in the intestinal lumen during maltose absorption is not high enough to account for the rates of glucose transport observed. The rate of appearance of glucose in the vascular effluent is determined by the concentration of disaccharide in the luminal fluid, and hexose, free in solution in the lumen, is not an obligatory intermediate in the process of disaccharide absorption.3. For R. pipiens more than 90% of the maltase activity in the system is present in the intestinal wall and the rate of maltose hydrolysis by maltase, free in the intestinal lumen, is found to be inadequate to account for the rates of appearance of glucose observed to occur in the lumen and in the vascular effluent. It is not possible to wash away maltase activity from the intestinal wall.4. The kinetic properties of maltase and trehalase acting in situ are of the Michaelis-Menten type; the apparent K(m) is 2 mM for maltase, and 3 mM for trehalase.5. The relationship which exists between the rate of absorption of glucose and the concentration in the luminal fluid of either disaccharide or free glucose is of the Michaelis-Menten type. Expressed in molar units, the apparent K(m) for the glucose transport is about one fifth that of the disaccharidase. The maximum rate of glucose transport observed is less than the maximum rate of disaccharide hydrolysis. In R. pipiens equimolar concentrations in the intestinal lumen of the monomer free glucose, or of the dimer, maltose, yield approximately equal rates of transport of the free hexose.6. It is concluded that in the amphibian, either intestine disaccharide hydrolysis and glucose transport are functions of separate subcellular systems which spatially are very closely related, or that the hydrolysis and transport are different facets of the activity of a common system.
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PMID:Disaccharide absorption by amphibian small intestine in vitro. 568 31

Sucrase-isomaltase (S-I) and maltase-glucoamylase (M-G) of the brush border have been purified to electrophoretic homogeneity from the pigeon small intestine. Heat-inactivated enzymes of crude homogenates of the pigeon intestinal mucosa, papain-solubilized enzymes and those obtained after chromatographic fractionation behaved in an identical manner. Depending on their sensitivity to heat treatment, the disaccharidases were identified to consist of two maltases; one, the heat-labile maltase, and the other, the heat-stable maltase. Sucrase and isomaltase constituted the thermolabile maltase and could be distinguished from each other. Maltase and glucoamylase formed the thermostable maltase the activities of which however, remained inseparable. Based on these results and in accordance with the nomenclature suggested by Dahlqvist & Telenius (1969), the pigeon intestinal disaccharidases were classified as follows: Maltase Ia = isomaltase, Maltase Ib = sucrase, and Maltase II = glucoamylase. DEAE-Cellulose chromatography did not resolve the two enzyme complexes but gel filtration of the active fractions recovered from the former step, resulted in their separation into two distinct peaks. Sucrase, isomaltase and a part of the maltase activity were recovered in the first peak which eluted close to the void volume. Glucoamylase and the remaining maltase activity were recovered in the second peak which appeared to have been retarded on the column because they were eluted much more slowly. The S-I and M-G complexes have an apparent molecular weight of 195 kd and 209 kd as determined by their gel-filtration pattern on Sepharose 6B. S-I hydrolysed alpha-glucosides such as maltose, sucrose and palatinose with a Km of 3.12 mM, 8 mM and 8.36 mM respectively and did not attack starch or dextran. In contrast, M-G catalysed the hydrolysis of starch, amylose and maltose with a Km of 3.12 mM, 7.59 mM and 3.52 mM respectively, and had no action on sucrose or palatinose. Both S-I and M-G were glycoproteins, and were inhibited by Ag+, Hg2+ and Tris but not by p-hydroxymercuribenzoate, iodoacetamide or imidazole. Na+ on the other hand activated both the enzyme complexes by about 20-25%. It is suggested that the molecular and catalytic properties of intestinal disaccharidases of pigeons do not differ considerably from those of Mammals.
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PMID:Studies on the intestinal disaccharidases of the pigeon. III. Separation, purification and properties of sucrase-isomaltase and maltase-glucoamylase. 620 6

The longitudinal distribution of the main brush border membrane hydrolases was studied in six entire human small intestine, one of which was found to be lactase-deficient. Sucrase and lactase activities were found to be highest in the jejunum, whereas glucoamylase activity rose steadily and reached its highest activity near the ileocecal valve. Maltase activity distribution was intermediate between that of sucrase and of glucoamylase. Neutral aminopeptidase, acid aminopeptidase and dipeptidyl peptidase IV activities tended to increase toward the end of the small bowel, the latter two activities rising more than the first one. Furthermore, the protein compositions of the brush border membrane in the jejunum and in the ileum were compared after electrophoresis on polyacrylamide gels and crossed-immunoelectrophoresis; protein patterns were found to be similar along the gut, and enzyme-specific activities varied in parallel with the amounts of their corresponding proteins. In the lactase-deficient intestine, the protein band corresponding to lactase was not visible. Maximal digestive capacity was thus localized in the jejunum only for disaccharides, and in the ileum for the more complex substrates, oligosaccharides, and peptides; this finding suggests that the ileum may play a greater role in their terminal digestion than is usually admitted.
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PMID:Longitudinal study of the human intestinal brush border membrane proteins. Distribution of the main disaccharidases and peptidases. 641 75

Lactase, maltase and sucrase activities were determined in samples of jejunal mucosa obtained by suction biopsy from 60 healthy adult German males. Primary adult hypolactasia ("lactase deficiency") was found in 8 subjects (13%). Maltase:lactase and sucrase:lactase activity ratios were significantly higher in post-weaning hypolactasia than in adult lactase persistence. Sources of variation in disaccharidase activities measured in biopsy tissue homogenates are discussed.
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PMID:Intestinal disaccharidase activities and activity ratios in a group of 60 adult German subjects. 678 Apr 38


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