The Aplysia californica Cl- pump is a P-type ATPase: evidence through inhibition studies

Abstract

Utilizing a proteoliposomal preparation containing Cl(-)-ATPase from Aplysia californica foregut, it was shown that orthovanodate inhibited Cl(-)-ATPase activity, ATP-dependent Cl- transport, ATP-dependent membrane potential change and ATP-dependent phosphorylation. N-ethylmalemide and p-chloromercurobenzoate also inhibited the Cl- pump biochemical and physiological transport characteristics. However, bafilomycin, azide, N, N'-dicyclohexylcarboiimide (DCCD), and efrapeptin had no effect on the Cl- pump biochemical or physiological characteristics, suggesting that this Cl- pump was a P-type ATPase. It was concluded that this P-type ATPase Cl- pump is the mechanism that is responsible for the net absorptive flux of Cl- in the A. californica foregut.