Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.108 (lactase)
 2,133 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. We investigated the chronic effects of a 4 week treatment with ethanol on functions and physicochemical properties of BBM of young and adult rats (2 and 7 months old respectively). 2. In the ethanol treated groups the cholesterol/phospholipid and the protein/lipid ratios as well as the D-glucose uptake and lactase specific activity and Vmax were increased. In spite of a minor alcohol consumption the adult group was the more affected. 3. Membranes from the ethanol fed rats were less fluid and more tolerant to the in vitro addition of ethanol.
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PMID:Age related changes in functions and physicochemical properties of rat jejunal brush border membrane after chronic ethanol administration. 809 80

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