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

Bile acids solubilize proteins from liver plasma membrane both in vivo and in vitro. The ability to solubilize the proteins is dependent on the species of bile acid. In this paper, the effect of phospholipid on the solubilization of a membrane-bound enzyme by bile acids was investigated in vitro. Taurocholate (TC) and tauroursodeoxycholate (TUDC) solubilized the enzyme, 5'-nucleotidase, from the liver plasma membrane of the rat in a concentration-dependent manner, although there was a great difference in their effect; at 40 mM, TC solubilized 55.4% of the original 5'-nucleotidase activity of the membrane, but TUDC only 5.7%. While lecithin alone had no solubilizing effect, its addition to the bile acids provoked a 10-fold increase in the solubilizing effect of TUDC, but virtually no change for TC, essentially equalizing the solubilizing effect of the two. Both TC-rich and TUDC-rich bile were obtained from rats infused with the respective bile acids via the jugular vein after their endogenous bile acid pool had been depleted. The solubilization effect of these biles was quite similar to the bile acid-lecithin mixtures. These findings demonstrate that lecithin enhances the ability of the bile acids to solubilize the membrane protein and eliminates the difference in the two bile acid species in their solubilizing ability.
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PMID:Effect of lecithin on the release of 5'-nucleotidase from liver plasma membrane of rat by bile acids. 302 30

Primary hepatocytes were cultured on collagen gel in serum-free, alpha-modified Eagle's minimum essential medium containing 0.1 microM insulin, 0.1 microM dexamethasone, 10 mM pyruvate and supplements such as glucagon, epinephrine or growth hormone. The activities of alkaline phosphatase, 5'-nucleotidase and gamma-glutamyltransferase were assayed in cell extracts prepared from the cultures. All three enzyme activities were induced by glucagon, epinephrine or dibutyryl cAMP. The maximally effective concentration of glucagon was 5-10 nM for both alkaline phosphatase and 5'-nucleotidase and 100 nM for gamma-glutamyltransferase. Only alkaline phosphatase activity was suppressed by growth hormone, which caused marked suppression at about 1 microU (0.25 ng)/ml. Taurocholate also induced both alkaline phosphatase and gamma-glutamyltransferase activities at 1 mM.
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PMID:Hormonal regulations of alkaline phosphatase, 5'-nucleotidase and gamma-glutamyltransferase activities in adult rat hepatocytes cultured in serum-free medium on collagen gel. 809 10