Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.6.3.1 (Mg2+-ATPase)
 1,484 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Recently, a gastric Mg(2+)-ATP-dependent phospholipid flippase was found. Here, the effects of ionophores and monovalent cations on the gastric flippase were examined. We found that translocation of the fluorescent analogue of phosphatidylcholine was inhibited by valinomycin in the presence of K(+). The inhibition depended on both the concentrations of valinomycin and K(+). Valinomycin did not inhibit translocation in the absence of K(+). Protonophores, carbonylcyanide-m-chlorophenylhydrazone (CCCP) and carbonylcyanide-p-(trifluoromethoxy)phenylhydrazone (FCCP), accelerated translocation by 190-270%. These increases were completely abolished by 2-methyl-8-(phenylmethoxy)imidazo-[1, 2-a]pyridine-3-acetonitrile (SCH 28080), a gastric flippase inhibitor. Since these protonophores did not affect the Mg(2+)-dependent ATPase activity that is responsible for phospholipid translocation by the flippase, the coupling ratio of the amount of transported phospholipids/the amount of hydrolyzed ATP was variable and seemed to depend on the state of the membrane bilayer, for example fluidity. Inhibition by the valinomycin-K(+) complex was abolished in the presence of CCCP or FCCP, indicating the valinomycin-K(+)-CCCP(FCCF) ternary complex did not inhibit the flippase.
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PMID:Effects of ionophores on the phospholipid flippase activity of gastric vesicles. 1060 27