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)

Differential centrifugation of rat small intestinal homogenates produced a crude brush border (BB) fraction that was enriched 15-fold for the marker enzymes, alkaline phosphatase and sucrase; contamination with mitochondrial enzymes, monoamine oxidase and succinate dehydrogenase, was minimal. ATP hydrolysis by this BB fraction was stimulated by addition of several anions to the incubation medium: HCO3 and Cl were equally effective in this regard, with NO3, NO2, SO4, and acetate being less stimulatory. SCN and CNO inhibited ATPase activity, whereas the divalent anion SO3 was stimulatory at low concentrations (less than 25 mM) but inhibitory at 100 mM. Maximum anion stimulation was observed at a Mg concentration of 0.5 mM, and pH optimum was 8.5. Kinetic analysis showed that HCO3 increased the Vmax without altering the Km for ATP; the Ka for this effect of HCO3 was 35 mM. This enzyme activity was completely inhibited by 20 mM L-phenylalanine, 10 mM L-cysteine, and 3 mM EDTA, compounds that also inhibited intestinal alkaline phosphatase. These results demonstrate the presence of anion-stimulated ATPase activity in rat small intestinal brush border and suggest that this activity may be related to intestinal alkaline phosphatase. The role of this enzyme in intestinal transport is not known, but could relate to the regulation of intestinal absorption and secretion.
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PMID:Anion-stimulated ATPase activity of brush border from rat small intestine. 15 3

The mucosal enzyme activities of 11 marker enzymes from the brush border, basolateral membrane, and lysosomes of 45 patients with an active duodenal ulcer (DU) were determined by analysis of homogenized biopsy specimens obtained from the duodenal bulb and descending duodenum at endoscopy. They were compared with activities measured in 22 controls. In the duodenal bulb lactase (p less than 0.005), neutral-alpha-glucosidase (p less than 0.0005), and monoamine oxidase (p less than 0.0005) were significantly decreased in DU patients. In the descending duodenum all the brush border enzymes except sucrase were significantly decreased when compared with controls. DU patients with inflammation in the biopsy specimens from the duodenal bulb had decreased levels of lactase (p less than 0.05), sucrase (p less than 0.05), neutral-alpha-glucosidase (p less than 0.05), leucyl-beta-naphthylamidase (p less than 0.05), and acid phosphatases (p less than 0.05) when compared with DU patients with normal histology in this region. In the descending duodenum the activities of leucyl-beta-naphthylamidase (p less than 0.05) were decreased in patients with inflammation compared with those without such histologic changes. DU patients who had taken antacids before the investigation had decreased activities of lactase (p less than 0.05) in the descending duodenum when compared with those who had not taken antacids. Activities of lactase (p less than 0.005), sucrase (p less than 0.005), neutral-alpha-glucosidase (p less than 0.05), and acid beta-glucuronidase (p less than 0.0005) in the descending duodenum were significantly lower in smokers than in non-smokers with active DU.
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PMID:Enzyme activities in the duodenal mucosa in duodenal ulcer patients. 292 38

The distribution of a series of mucosal enzymes along the large bowel was studied by analysis of homogenized biopsy specimens from five different segments, obtained from 20 control patients. The activities varied significantly between the segments for the membrane enzymes lactase (p less than 0.005), alkaline phosphatase (p less than 0.0005), leucyl-beta-naphthylamidase (p less than 0.0001), and 5'-nucleotidase (p less than 0.001) and the mitochondrial enzyme monoamine oxidase (p less than 0.0005) when tested by analysis of variance modified for repeated measurements. When paired comparisons between segments were evaluated, the enzyme activities of the proximal large bowel were significantly higher than those of distal segments. The levels of sucrase, neutral-alpha-glucosidase, gamma-glutamyltransferase, and lysosomal enzymes remained unchanged throughout the large intestine, as did the protein to DNA ratio. The results are compatible with the theory that different segments of the large bowel have different functions.
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PMID:Longitudinal distribution of mucosal enzymes in the human large bowel. 377 57