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)

Interactions of lipids and proteins in isolated rat intestinal microvillus membranes were examined by studying the temperature dependence of enzyme activities and of D-glucose transport in relation to the membrane lipid thermotropic transition observed by fluorescence polarization (26 +/- 2 degrees C) and differential scanning calorimetry (23--39 degrees C). Two groups of activities were defined. Enzymes of the first group, comprising lactase, maltase, sucrase, leucine aminopeptidase, and gamma-glutamyl transpeptidase, all yielded a single slope on the Arrhenius plot in the range 10--40 degrees C and did not appear to experience functionally the effects of the lipid thermotropic transition. Each activity of the second group, comprising calcium- and magnesium-dependent adenosine triphosphatases, p-nitrophenylphosphatase, and D-glucose transport, showed a change in the slope of the Arrhenius plot in the range 25--30 degrees C, corresponding to the lower region of the lipid transition. The terms "extrinsic" and "intrinsic" activities could be applied to these groups. Delipidation of the particulate p-nitrophenylphosphatase removed the discontinuity in the Arrhenius plot. Subsequent relipidation with a variety of lipids restored a break point, but the temperature corresponded to the original discontinuity (25--29 degrees C) rather than to the phase transition temperature of the exogenous lipid added.
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PMID:Functional interactions of lipids and proteins in rat intestinal microvillus membranes. 3 92

In order to investigate the relationship between dietary amino acids and protein, as well as the activities of intestinal sucrase and leucine aminopeptidase in rats, the effects of an amino acid imbalance on these enzyme activities were studied. The amino acid imbalance was created by adding 8% of an indispensable amino acid mixture lacking threonine to a 6% casein diet supplemented with 0.3% methionine. The food intake and growth of rats fed the imbalanced diet ad libitum were depressed, and the segmental weights of the small intestine and its sucrase activity were clearly lower than those of rats fed the basal diet. The effect of the imbalanced diet under pair-feeding condition on the sucrase activity was similar to that under an ad libitum feeding condition. The food intake and segmental sucrase activity, that is, sucrase activity per length of the small intestine, of rats injected with cortisol (1 mg/day) and fed the imbalanced diet were not depressed, although administration of insulin (1.5 U/day) had no effect on the food intake or segmental sucrase activity. Force-feeding stimulated growth of rats receiving the imbalanced diet, as well as increasing their segmental sucrase activities. The effects of these different conditions on the leucine aminopeptidase activity of rats receiving the imbalanced diet were obscure. These results suggest that changes in segmental sucrase activity might be mediated by stimulating factors in food intake affected by the composition of ingested amino acids and protein together with sucrose in the gastrointestinal lumen.
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PMID:Effect of an amino acid imbalance on intestinal sucrase and leucine aminopeptidase activities in rats. 12 Apr 27

The release of proteins, sucrase (SA), maltase (MA), leucine aminopeptidase (LA) and alkaline phosphatase (AP) activity from rat jejunum by sodium deoxycholate (DOC) was studied by an in vivo perfusion technique. In our experimental conditions, a 2 mmol/1 DOC perfusion for 30 min induced a marked and reversible release of proteins and hydrolases. When specific activities were considered, each enzyme showed a distinct release pattern. Significantly, the SA release was largely increased, the AP release was decreased and there was no correlation between the releases of SA and AP. Furthermore, the various enzymes recovered into the lumen were solubilized at different extents. SA was chiefly present in a soluble and AP in a particular form. The microscopical appearances showed a slight exfoliation of the epithelial cells from the villous tips but no specific changes when compared to the control group. The results are discussed in terms of enzymic localization in the brush border membrane; SA would be located very superficially in the surface membrane and AP buried in the membrane and less accessible than the other enzymes.
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PMID:Rat intestinal brush border enzymes release by deoxycholate in vivo. 34 19

The in-vivo effects of sodium deoxycholate (DOC) at low concentrations on the release of protein and some brush border hydrolases, sucrase (SA), maltase (MA), leucine aminopeptidase (LA), alkaline phosphatase (AP), have been investigated in the rat by a jejunal perfusion technique. During perfusion with DOC (0.125 or 0.25 mmol/l), enzyme release was not enhanced. After removal of DOC from the perfusion solution with 0.125 mmol/l DOC, there was a steady release of SA, MA and AP although enzyme release was increased linearly in the control and the 0.25 mmol/l DOC groups. The results also confirm the deep localization of AP within the membrane.
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PMID:Do low doses of deoxycholate modify the release of rat jejunal brush border hydrolases? 37 3

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 effect of dietary amino acids on jejunal sucrase (EC 3.2.1.26) and leucineaminopeptidase (EC 3.4.11.1, LAPase) activities in rats was studied. Rats were force-fed a 10% complete amino acid diet or valine-free diet. The sucrase and LAPase activities in rats force-fed the valine-free diet for 2 days were significantly lower than those in rats force-fed the complete amino acid diet, although the specific activities of these enzymes in the isolated brush border fragment were 10 times higher than those in the mucosa, and most of the activities of these enzymes in the mucosa were localized in the isolated brush border fragment. Results of experiments undertaken to investigate the effects of dietary amino acids during the initial period after the dietary alteration on the sucrase and LAPase activities showed that decreases in the activities of these enzymes in rats force-fed the valine-free diet appeared by 26 hours after the first feed administration; whereas, incorporation of dietary 14C-amino acids administered in the first feed administration into the mucosal protein was significantly lower in rats receiving the valine-free diet than in rats receiving the complete amino acid diet by 7 hours following the first feed administration. These results suggest that decreases in availability of dietary amino acids in the valine-free diet for protein formation in the small intestinal mucosa during the initial period caused the decreases in the sucrase and LAPase activities localized in the brush border membrane.
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PMID:Effect of dietary amino acids on jejunal sucrase and leucineaminopeptidase activities in rats. 66 Mar 2

The activities of the digestive enzymes, maltase [EC 3.2.1.20], sucrase [EC 3.2.1.26], trehalase [EC 3.2.1.28], Leucine aminopeptidase [EC 3.4.11.1], and alkaline phosphatase [EC 3.1.3.1] were measured in various regions of the small intestine of rats. The activities of all these enzymes were much higher in the jejunum than in the ileum, and in the distal regions of the ileum no sucrase, trehalase or alkaline phosphatase activity was detected. In the jejunum, the activities of all the enzymes tested exhibited clear circadian variations with the highest activity at 0000-0400 h and the lowest at 1200 h when the rats were fed ad libitum. In the ileum, maltase and sucrase also exhibited circadian variations, but the amplitude of the rhythm was smaller than that in the jejenum. Trehalase and alkaline phosphatase did not show any circadian variation in the ileum. Leucine aminopeptidase showed a circadian variation in the ileum with the same amplitude as in the jejunum. The phase of the circadian variations shifted about half a day when the rats were fed in the daytime, but the amplitude of the rhythm did not change.
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PMID:Circadian rhythms in digestive enzymes in the small intestine of rats. I. Patterns of the rhythms in various regions of the small intestine. 122 10

It has been shown previously that insulinlike growth factors (IGFs) stimulate the proliferation of intestinal crypt cells in vitro. To examine the in vivo effects of IGF-I on mucosal adaptation, three groups of Sprague-Dawley rats underwent 80% jejunoileal resection. Miniosmotic pumps were then inserted under the skin immediately after resection to deliver vehicle (resected control), 1.5 mg/kg per day of IGF-I, or 1.5 mg/kg per day of des-(1-3)-IGF-I (des-IGF-I). Des-IGF-I is a truncated form of IGF-I that binds as well to type I IGF receptors but less tightly to several forms of IGF-binding proteins (IGFBPs) than IGF-I. Ad libitum food intake did not differ among the three resected groups. Body weight gains were greater in animals receiving des-IGF-I than in those receiving IGF-I, which were greater than resected controls. All animals were killed 7 days postoperatively, and the remaining small intestine was removed and divided at the anastomotic site. Both IGF-I and des-IGF-I induced hyperplasia (increased DNA and protein content) in the duodenojejunum but not in the ileum. IGF-I and des-IGF-I were equally active. In contrast, sucrase, maltase, and leucine aminopeptidase activities were greater only in the ileum of animals receiving IGF-I and des-IGF-I than in resected controls. Although more potent in stimulating overall body weight gain, des-IGF-I was not more potent than IGF-I when duodenal and ileal responses were determined. IGF infusion (IGF-I greater than des-IGF-I) increased the levels of circulating IGFBP-3 and IGFBP-2, which may act to modulate the biological effectiveness of the infused peptides. These results suggest that both IGF-I and des-IGF-I may have potential as therapeutic agents for short bowel patients.
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PMID:Truncated and native insulinlike growth factor I enhance mucosal adaptation after jejunoileal resection. 137 79

The antiprotozoal drug metronidazole, when administered orally at a dose level of 100 mg/kg body wt. daily for 7 days to rats, brought about significant elevation of renal brush-border-membrane-bound hydrolytic enzymes, such as alkaline phosphatase, maltase, sucrase, and leucine aminopeptidase (LAP). Kinetic analysis of the enzymes (substrate saturation) indicated that the drug produced an increase in the maximum of apparent initial enzyme velocity (Vmax), while the substrate affinity constant (Km) remained unaltered. These changes were not recovered to the normal level even after the drug regimen was stopped and the animals were allowed to recover for a period of 7 days. Lipid analysis of brush border membrane (BBM) revealed a significant elevation in the cholesterol, phospholipid, and ganglioside levels, while no marked change was recorded in triglyceride, free fatty acid and plasmalogen. Study of the temperature-dependent parameters of the enzymes showed that metronidazole induced a shift in the transition temperature (To) in LAP with nearly total reversibility in the recovery group. No such change was seen in the other enzymes. However, there also was a lowering in the energy of activation (Ea) below To, which returned to normal after the treatment was withdrawn.
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PMID:Changes in membrane-bound hydrolases by metronidazole in rat renal brush border. 141 Aug 3


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