Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.3.5 (5'-nucleotidase)
 3,167 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The influence of two surface-active food additives on the integrity and permeability of rat ileal mucosa has been studied. We determined the activity of N-acetyl-beta-glucosaminidase, a lysosomal enzyme, in the rat intestinal lumen after deposition of polyoxyethylene (20) sorbitan monostearate (polysorbate 60; Tween 60) or polyoxyethylene (20) sorbitan monooleate (polysorbate 80; Tween 80) in a section of ligated, cannulated gut. We also determined the activities of N-acetyl-beta-glucosaminidase, alkaline phosphatase, 5'-nucleotidase and phospholipase A2 in mixtures of isolated mucosal cells and polysorbate 60 or polysorbate 80. The activity of N-acetyl-beta-glucosaminidase was increased in the luminal contents of the cannulated gut 15 min after deposition of either polysorbate 60 or polysorbate 80 (10 mg/ml fluid instilled into gut). It was also increased in mixtures of mucosal cells and polysorbate 60 or polysorbate 80 (0.1-10 mg/ml). In contrast, the activities of alkaline phosphatase and 5'-nucleotidase were unaffected and that of phospholipase A2 was decreased by the presence of either polysorbate. These findings indicated that polysorbate 60 and polysorbate 80 released lysosomal enzymes from the intestinal mucosal cells and that these agents might damage the intestinal mucosa and increase its permeability. We therefore determined the intestinal permeability to sodium fluorescein in the absence and presence of polysorbate 60 or 80 and found that the permeability was slightly increased in the presence of either of the compounds at concentrations of 10 mg/ml fluid instilled into gut. It is possible therefore that surface-active food additives might impair the function of the mucosal barrier and increase the permeability of the gut to potentially toxic and pathogenic molecules.
 ...
PMID:Influence of surface-active food additives on the integrity and permeability of rat intestinal mucosa. 609 20

1 A microsomal fraction was prepared from human umbilical arteries by differential centrifugation. The preparation was capable of an oxalate-stimulated Ca2+ uptake at a mean rate of 0.74 nmol Ca2+ mg-1 protein min-1 which could be inhibited by a Ca2+ ionophore, A 23 187, and by Tween 80. 2 The rate of Ca2+ uptake in the fraction obtained by density gradient fractionation paralleled 5'-nucleotidase activity suggesting that vesicles of predominantly sarcolemmal origin were responsible for the microsomal Ca2+ uptake. 3 Cyclic adenosine 3',5'-monophosphate-dependent protein kinase enhanced membrane phosphorylation but did not affect Ca2+ uptake. Preincubation with alkaline phosphatase reduced membrane phosphorylation to a greater extent than Ca2+ uptake. These data are not in favour of a close correlation between Ca2+ uptake and phosphorylation. 4 None of 15 vasodilator drugs (bencyclane, carbocromen, diazoxide, dilazep, hydralazine, indapamide, isosorbide dinitrate, methyl-isobutyl-xanthine, minoxidil, naftidrofuryl, nitroglycerine, prenylamine, sodium nitroprusside, tetracaine, and verapamil) had any effect on Ca2+ uptake at 10(-5) M. This suggests that vasodilator drugs do not act by a direct influence on the Ca2+ pumps of vascular smooth muscle cells.
 ...
PMID:Effects of vasodilator drugs, alkaline phosphatase, and cyclic AMP-dependent protein kinase on the 45calcium uptake of sarcolemmal microsomes from human umbilical arteries. 625 79

The ability of nonionic detergents to solubilize the membrane-bound enzymes of the brush-border plasma membrane of Hymenolepis diminuta was investigated. Of the detergents tested (Triton X-100, Tween 80, Brij 35, Lubrol PX and WX, W-1, and beta-octyl-D-glucoside), only Triton was an effective solubilizing agent. Optimal solubilization was achieved by incubating an isolated fraction of the brush-border membrane in the presence of 1% Triton X-100 for 60 min at 37 C, followed by centrifugation at 100,000 g for 60 min at 25 C. This treatment resulted in solubilization of 94% of the alkaline phosphohydrolase, 91% of the phosphodiesterase and ribonuclease, and 88% of the 5'-nucleotidase activities. The pH optima for enzymes solubilized in nonionic and ionic detergents (Triton and sodium dodecyl sulfate, respectively) did not differ. Isoelectric focusing of the Triton-solubilized material demonstrated the presence of at least 14 polypeptides, a majority of which had isoelectric points below pH 7.
 ...
PMID:Solubilization of the membrane-bound enzymes of the brush-border plasma membrane of Hymenolepis diminuta (Cestoda) using nonionic detergents. 628 6