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)

Variations in the dietary fatty acid composition and cholesterol content are associated with alterations in the intestinal uptake of hexoses and lipids in control and diabetic rats. Changes in the composition of the brush membrane (BBM) lipids may provide a possible mechanism for the observed alterations in transport properties. Accordingly, control and streptozotocin diabetic animals were fed one of four isocaloric semisynthetic diets for two weeks: beef tallow with low cholesterol, beef tallow with high cholesterol, fish oil with low cholesterol or fish oil with high cholesterol. BBM were prepared and assessed for marker enzyme activity and lipid composition. Fish oil feeding was associated with a reduction in total phospholipid content in control and diabetic jejunal and ileal BBM; this fall in total phospholipids was due to a reduction in BBM sphingomyelin. Cholesterol supplementation increased control jejunal BBM sucrase activity in animals fed beef tallow but reduced sucrase activity in animals fed fish oil. In fish oil fed diabetic animals, jejunal and ileal BBM alkaline phosphatase activity was increased with cholesterol supplementation. The elevation in BBM total phospholipids (phosphatidylethanolamine) associated with diabetes in beef tallow fed animals was not observed in the jejunal BBM of animals fed fish oil or in the ileal BBM of animals fed fish oil with high cholesterol. Thus, (a) feeding an omega-3 polyunsaturated fatty acid diet (fish oil) reduced total phospholipid content in BBM of control and diabetic animals, primarily due to a reduction in sphingomyelin; and (b) feeding an omega-3 polyunsaturated fatty acid diet or dietary cholesterol supplementation alter the activity of BBM enzymes. These results suggest that variations in dietary fat composition and the associated changes in BBM composition and enzyme activity contribute to altered intestinal function in diabetes.
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PMID:Isocaloric modification of dietary lipids influences intestinal brush border membrane composition in diabetic rats. 180 79

To examine age-related changes in the morphology of intestinal brush border membrane (BBM; microvilli) and specific activities of intestinal BBM enzymes including alkaline phosphatase (ALP), gamma-glutamyl transpeptidase (gamma-GT), and disacchridase, four groups of Wistar rats were sacrificed at 2.5 wk, 5 wk, 5 mon and 23 mon. In an electron microscopic examination, morphologically a less dense BBM structure in the duodenum of rats aged 23 mon was observed than that of rats aged 5 mon. Specific activity of ALP in the duodenum from 5-mon-old rats was significantly higher than from rats aged 2.5 wk and 23 mon. The mucosal tissues from 5-wk-old rats had significantly higher specific activity of gamma-GT than did tissues from the other ages. In sucrase and maltase specific activities, 5-mon-old rats had higher activities of these enzymes than other age groups, especially 2.5-wk- and 23-mon-old rats. There was also a significant effect of site on intestinal BBM enzyme activities in post-weanling rats. Regional gradients of ALP and gamma-GT along the entire small intestine (duodenum > jejunum > ileum) were remarkable. Disaccharidase activities peaked in the jejunum and declined toward both the duodenum and ileum. Taken together the result obtained here suggested that 5-mon-old rats had the most elevated intestinal function. This result also strongly indicated that the structure of the intestinal BBM and development of intestinal BBM enzymes in Wistar rate were markedly influenced by age during the postnatal period.
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PMID:Influence of age on duodenal brush border membrane and specific activities of brush border membrane enzymes in Wistar rats. 1110 54

The activities of lactase, sucrase and alkaline phosphatase (AP) were studied in intestinal brush border membranes of control and toxin-treated rabbits. Purified Shiga toxin (Stx) exposure to ileal mucosa inhibited activities of brush border enzymes by 50%. Kinetic analysis revealed that the observed decrease in BBM enzyme activities was due to reduced V(max) with no change in the affinity constants of the systems. The observed changes in enzyme activities were corroborated by Western Blot analysis of lactase, sucrase and AP. The mRNA levels encoding sucrase and lactase proteins in control and Shiga toxin-treated rabbit ileum did not show any change in the rabbit ileum. Histopathological analysis showed short, blunt villi with increased number of inflammatory cells in the lamina propria and extrusion of cells in to the lumen of Stx-treated rabbit ileum. The present findings suggest that Shiga toxin act by inhibiting protein synthesis of these brush border functional proteins beyond their transcriptional level and by the direct damage to intestinal epithelium, which could be implicated in the pathogenesis of diarrhea.
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PMID:Shiga toxin exposure modulates intestinal brush border membrane functional proteins in rabbit ileum. 1644 89

Intestinal alkaline phosphatase (IAP) is a brush-border membrane ectoenzyme (BBM-IAP) that is released into the lumen (L-IAP) after a high-fat diet. We examined the effects of oil feeding and the addition of mixed-lipid micelles on the formation of L-IAP in oil-fed rat intestine, Caco-2 cell monolayers, and mouse intestinal loops. We localized IAP in the duodenum of rats fed corn oil using fluorescence microscopy with enzyme-labeled fluorescence-97 as substrate. Four hours after oil feeding, L-IAP increased approximately 10-fold accompanied by the loss of BBM-IAP, consistent with BBM-IAP release. Rat IAP isozyme mRNAs progressively increased 4-6 h after oil feeding, followed by the increase of IAP activity in the subapical location at 6 h, consistent with the restoration of IAP protein. Postprandial lipid-micelle components, sodium taurocholate with or without oleic acid, mono-oleylglycerol, cholesterol, or lysophosphatidylcholine (lysoPC) were applied singly or as mixed-lipid micelles to the apical surface of polarized Caco-2 cell monolayers. LysoPC increased L-IAP >10-fold over basal release. LysoPC released IAP into the apical medium more than other intestinal brush-border enzymes, 5'-nucleotidase, sucrase, aminopeptidase N, and lactase, without comparable lactate dehydrogenase release or cell injury. LysoPC increased human IAP mRNA levels by 1.5-fold in Caco-2 cells. Luminally applied lysoPC also increased release of IAP preferentially in mouse intestinal loops. These data show that lysoPC accelerates the formation of L-IAP from BBM-IAP, followed by enhanced IAP synthesis, suggesting the role that lysoPC might play in the turnover of brush-border proteins.
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PMID:Role of lysophosphatidylcholine in brush-border intestinal alkaline phosphatase release and restoration. 1940 15