Sterol Modulation of the Plasma Membrane H+-ATPase Activity from Corn Roots Reconstituted into Soybean Lipids

摘要: A partially purified H+-ATPase from the plasma membrane (PM) of corn (Zea mays L.) roots was inserted into vesicles prepared with soybean (Glycine max phospholipids and various concentrations individual sterols using either a freeze-thaw sonication or an octylglucoside dilution procedure. Both methods yielded functional enzyme that retained its native characteristics. We have investigated effects typical plant (i.e. sitosterol, stigmasterol, 24-methylcholesterol) on both ATP hydrolysis H+ pumping by reconstituted root PM ATPase. also checked influence cholesterol two unusual sterols, 24-methylpollinastanol 14[alpha],24-dimethylcholest-8-en-3[beta]-ol. Here we present evidence for sterol modulation activity. In particular, stigmasterol were found to stimulate pump, especially when at 5 mol%, whereas all other tested behaved as inhibitors any concentration in proteoliposomes. situations shown be more sensitive environment than hydrolysis. Our results suggest occurrence binding sites H+-ATPase.