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

---

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

The dose relationship between medroxyprogesterone acetate (MPA), a long acting contraceptive, and rat intestinal digestive and absorptive functions has been investigated. The study revealed that the activities of brush border sucrase, lactase and leucine aminopeptidase were stimulated only at high doses, viz 70 mg/kg (180 mumol/kg) body weight and above, whereas the activity of alkaline phosphate was depressed at comparatively low dose (17.5 mg/kg; 45 mumol/kg body weight). This decrease was found to be significant (p less than 0.001) at all the doses tested. The inhibition in the intestinal uptake of calcium paralleled the decrease in alkaline phosphatase activity. Relatively high amount of MPA (140 mg/kg; 360 mumol/kg) was required to augment the uptake of glucose and amino acid. The results obtained do not indicate a close relationship between the dose of the drug and the extent of alteration in the rat intestinal digestive and absorptive functions. The study appears to confirm the association between brush border enzymes activities and uptake of nutrients in rat intestine.
...
PMID:Effect of various doses of medroxyprogesterone acetate on intestinal functions in rats. 230 1

The present studies were conducted to determine if diets containing a large amount of fat stimulate the regeneration of damaged intestinal mucosa in the presence or absence of essential fatty acid deficiency. To simulate injury, male Sprague-Dawley rats were given methotrexate, 2.5 mg/kg body wt, subcutaneously for 3 consecutive days. Twenty-four hours after the last methotrexate injection, rats were placed on diets containing either 0%, 1%, or 10% safflower oil. Mucosal weight, protein, deoxyribonucleic acid, maltase, sucrase, lactase, alkaline phosphatase, leucine aminopeptidase, and fatty acids were all determined 3 and 12 days after methotrexate. Crypt-cell production rates were also determined. Essential fatty acid deficiency was confirmed in the 0% safflower oil group, in which triene-tetraene ratios were greater than 0.4. Mucosal weight, deoxyribonucleic acid, protein content, and villus height were all greater in the 1% safflower oil group than in the 0% group at 12 days. In the ileum, 1-h thymidine incorporation was greater in the 0% safflower oil group than in the other two groups. No differences in any of the parameters studied were observed between the 1% and 10% groups. These results suggest that diets deficient in essential fatty acids may impair the recovery of intestinal mucosa from injury.
...
PMID:Effects of dietary lipids on recovery from mucosal injury. 232 15

The effect of methylglyoxal on protein -SH and -NH2 groups in cytosolic and membranous fractions of epithelial cells lining the gastrointestinal tract of rat was investigated, using isolated villus and crypt cells (enterocytes) and colonocytes. It was found that 11-12% cytosolic protein -SH and 14-17% membrane protein -SH groups were lost when villus and crypt cells were treated with 2 mM methylglyoxal. In colonocytes, the corresponding loss in protein -SH groups was 46 and 30% under the same treatment. Similarly, 27-37% protein -NH2 group in the cytosolic fraction and 18-19% protein -NH2 group in membranous fractions of the enterocytes were lost by 2 mM methylglyoxal treatment. In colonocytes, the loss of protein -NH2 group was 30 and 15% in cytosolic and membranous fractions, respectively, under the same treatment. Effect of methylglyoxal on activity of various brush border enzymes such as alkaline phosphatase, gamma-glutamyl transpeptidase, leucine aminopeptidase, Mg2(+)-ATPase, sucrase and lactase was also studied. Alkaline phosphatase and gamma-glutamyl transpeptidase activities were inhibited to the extent of 30 and 15% respectively. There was no significant change in the activities of other enzymes after treating the brush border vesicles with 2 mM methylglyoxal. These findings show that methylglyoxal can cause loss of protein thiol and amino groups and enzyme activity in mucosal cells of rat gastrointestinal tract and the effect is more pronounced in colonocytes, which are in constant contact with bacterial metabolites.
...
PMID:Effect of methylglyoxal on protein thiol and amino groups in isolated rat enterocytes and colonocytes and activity of various brush border enzymes. 234 Nov 60

Oral administration of cimetidine, an antiulcerogenic drug, at a dose of 100 mg per kg body weight in mice, caused significant inhibition of glucose and amino acid uptake in small intestinal segments either after 2 and 24 h (single treatment) or 15 days (daily). Cimetidine also caused a significant decrease in intestinal brush border membrane associated enzymes, sucrase, lactase, maltase and alkaline phosphatase, but increases the activity of leucine aminopeptidase. Kinetic analysis indicated that cimetidine decreased the maximum of apparent initial enzyme velocity (Vmax) of disaccharidases, while substrate affinity constant (Km) was not altered, indicating the noncompetitive nature of inhibition. However, the inhibition of alkaline phosphatase was found to be of mixed type as both Km and Vmax were altered. In vitro addition of cimetidine also produced significant inhibition of enzymes, the inhibition constant (Ki) for sucrase, lactase, maltase and alkaline phosphatase being 22.8, 4.5, 11.5 and 4.8 mM, respectively. It was further observed that in vitro addition of cimetidine also decreased Vmax in case of maltase, sucrase and lactase, Km was unchanged, whereas in case of alkaline phosphatase there was a decrease in Vmax and increase in Km, as compared to the controls.
...
PMID:Effect of cimetidine on intestinal absorption & digestive functions in mice. 237 90

A blotting method is described to detect enzymes that do not normally yield a colored product. The method can be used for dot blotting as well as blotting after gel electrophoresis of many enzymes if the reactions they catalyze can be coupled to an oxidase or a dehydrogenase. The latter, designated "auxiliary enzymes," are preimmobilized on membranes of nitrocellulose or positively charged nylon and the reaction they catalyze is coupled with reduction of tetrazolium salt to yield colored formazan on areas of the transfer membrane occupied by the blotted enzymes. In the examples reported here, preimmobilized glucose oxidase, L-amino acid oxidase, xanthine oxidase, malate dehydrogenase, and a mixture of hexokinase and glucose-6-phosphate dehydrogenase were used as auxiliary enzymes to detect blotted invertase, leucine aminopeptidase, purine nucleoside phosphorylase, fumarase, and adenylate kinase, respectively. Detection limits varied, but never exceeded 100 ng for these enzymes. After blotting from polyacrylamide gels, the fumarase assay was the most sensitive of those investigated, detecting 10 ng of enzyme used for electrophoresis. Invertase, a glycoprotein, was detected with higher sensitivity on nitrocellulose membranes when concanavalin A was present on the membrane in addition to the auxiliary enzyme, glucose oxidase. On blots from isoelectric focusing gels, the assay detected two isozymes of purine nucleoside phosphorylase in a sample from calf spleen and at least five isozymes of this enzyme in lysates from human red cells.
...
PMID:Activity staining of blotted enzymes by reaction coupling with transfer membrane-immobilized auxiliary enzymes. 245 38

The activities of intestinal brush border membrane (BBM) enzymes alkaline phosphatase, maltase, lactase, sucrase, gamma-glutamyl transpeptidase and leucine aminopeptidase were determined in intestinal homogenates and purified BBMs from control, heat-stable and heat-labile enterotoxin treated mice. The activities of all the enzymes except lactase were decreased significantly (p less than 0.01) in homogenates while increased significantly (p less than 0.001) in BBMs of experimental groups as compared to controls. Calmodulin activities were increased significantly (p less than 0.01) as compared to control in heat-stable enterotoxin treated mice but remained unaltered in heat-labile enterotoxin treated mice. DNA contents of intestinal homogenates were decreased in experimental groups demonstrating the decrease in cell number in these groups. The altered BBM enzyme activities could not be attributed to changes in calmodulin activities. The increase in enzyme activities in BBMs may reflect a compensatory phenomenon in the remaining cells.
...
PMID:Effect of heat-stable and heat-labile enterotoxins of Escherichia coli on intestinal brush border membrane enzymes of mice. 257 May 78

Oral administration of antiulcerogenic drug ranitidine significantly inhibits glucose and amino acid uptake in small intestinal segments. It also inhibits activities of brush border membrane disaccharidases and alkaline phosphatase but increases the activity of leucine aminopeptidase. Kinetic analysis reveals noncompetitive and mixed type of inhibition for disaccharidases and alkaline phosphatase, respectively. In vitro addition of the drug to membrane preparation shows similar type of results as seen in vivo with the inhibition constant (ki) for sucrase, lactase, maltase and alkaline phosphatase as 12.5, 5, 11.5 and 19.5 mM, respectively.
...
PMID:Effect of antiulcerogenic drug, ranitidine, on intestinal absorption and digestive functions in mice. 263 81

A phospholipase A2 activity directed against phosphatidylcholine was previously described in brush-border membrane from guinea pig intestine (Diagne, A., Mitjavila, S., Fauvel, J., Chap, H., and Douste-Blazy, L. (1987) Lipids 22, 33-40). In the present study, this enzyme was solubilized either with Triton X-100 or upon papain treatment, suggesting a structural similarity with other intestinal hydrolases such as leucine aminopeptidase, sucrase, or trehalase. The papain-solubilized form, which is thought to lack the short hydrophobic tail responsible for membrane anchoring, was purified 1800-fold to about 90% purity by ion exchange chromatography on DEAE-Sephacel, gel filtration on Ultrogel AcA44, and hydrophobic chromatography on phenyl-Sepharose. Upon polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate, a main band with an apparent molecular mass of 97 kDa was detected under reducing and nonreducing conditions. In the latter case, phospholipase A2 activity could be recovered from the gel and was shown to coincide with the 97-kDa protein detected by silver staining. The enzyme activity was unaffected by EGTA and slightly inhibited by CaCl2. The purified enzyme displayed a similar activity against phosphatidylcholine and phosphatidylethanolamine, whereas 1-O-alkyl-2-acyl-sn-glycero-3-phosphocholine hydrolysis was reduced by 50% compared to diacylglycerophospholipids. Using phosphatidylcholine labeled with either [3H]palmitic acid or [14C]linoleic acid in the 1- or 2-positions, respectively, the purified enzyme catalyzed the removal of [3H]palmitic acid, although at a lower rate compared to [14C]linoleic acid. This resulted in the formation of sn-glycero-3-phosphocholine, but only 1-[3H]palmitoyl-sn-glycero-3-phosphocholine was detected as an intermediary product. In agreement with this, 1-acyl-2-lyso-sn-[14C]glycero-3-phosphocholine was deacylated at almost the same rate as the sn-2-position of phosphatidylcholine. Since upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the two hydrolytic activities were detected at the same position as 97-kDa protein, the enzyme is thus considered as a phospholipase A2 with lysophospholipase activity (phospholipase B), which might be involved in phospholipid digestion.
...
PMID:Purification of a new, calcium-independent, high molecular weight phospholipase A2/lysophospholipase (phospholipase B) from guinea pig intestinal brush-border membrane. 272 44

The interaction between malnutrition and exposure to a mucosal damaging agent, difluoromethylornithine (DFMO), was examined by monitoring the small-intestinal changes in weanling rats. Malnutrition as induced by the expanded-litter method resulted in severe reduction in body weights in the expanded litters as compared to normal litters. Subsequent treatment of malnourished and well-nourished pups with DFMO for 7 days resulted in decreases in small-intestinal weights and enzyme contents. A 2 factors (well-nourished and malnourished) by 2 factors (DFMO-treated and nontreated) analysis of variance showed no interaction between malnutrition and DFMO treatment in terms of food intake, total mucosal protein, and contents of enterokinase, leucine aminopeptidase and sucrase. Very slight and insignificant interactions (p less than or equal to 0.2) were found for body weights, intestinal weights and total DNA content. Only one parameter studied, the maltase content, showed significant interaction between malnutrition and DFMO treatment (p less than 0.05). Three weeks after the withdrawal of DFMO, essentially all the changes caused by DFMO recovered. But those changes caused by malnutrition did not, such that the malnourished group, whether treated with DFMO or not, still remained significantly less than the control group in their small-intestinal parameters. Analysis of variance showed no interaction between malnutrition and DFMO treatment in the recovery phase. The results suggest that malnutrition is a more important factor in determining the intestinal damage and that malnutrition in the immediate postnatal period does not increase the sensitivity of the small intestine to the damaging effect of DFMO.
...
PMID:Interaction of malnutrition and difluoromethylornithine-induced intestinal mucosal damage: degree of severity and subsequent recovery. 285 68

The activities of enteropeptidase, alanine aminopeptidase, sucrase, and leucine aminopeptidase were determined in mucosa biopsies taken from three defined places of the duodenum and in duodenal juice. We examined 23 adults with a histological proven normal mucosa and 10 patients suffering from duodenitis grade I. Using multivariate evaluation of all the four enzyme activities of the three mucosa sites, we could differentiate duodenitis from normal mucosa with an efficiency of 88%.
...
PMID:[Biochemical diagnosis of duodenitis]. 287 20


<< Previous 1 2 3 4 5 6 7 8 Next >>

---