H+‐translocating ATPase and Na+/H+ antiport activities in the plasma membrane of the marine alga Platymonas viridis

[摘要]

Proton transport by the vanadate-sensitive ATPase in plasma membrane (PM) vesicles from the marine unicellular microalga Platymonas viridis was investigated. The ATP-dependent generation of ΔpH across the membranes of PM vesicles was followed by the changes in the absorbance of the aminoacridine probe. Acridine orange, Na⁺ caused the decay of ΔpH generated by the ATPase, the rate of the decay being dependent on the concentrations of Na⁺ added. The phenomenon was specific for Na⁺. Amiloride inhibited Na⁺-dependent ΔpH decay. The experiments support the idea of a Na⁺-extruding mechanism (H⁺-translocating ATPase plus Na⁺/H⁺ antiporter) operating in the PM of marine alga Pl. viridis.

[学科分类] 生物化学/生物物理

[关键词] H+-ATPase;Na+/H+ antiport;Marine alga;Plasmalemma;Platymonas viridis;ΔpH;electrochemical H+ potential difference;CCCP;m-chlorocarbonylcyanide phenylhydrazone;DTT;dithiothreitol;EGTA;ethyleneglycol-bis(β-aminoethyl ether) N;N;N′;N′-tetraacetic acid