Inhibition of a Cl- - transporting P-type ATPase in Aplysia gut

Utilizing a basolateral membrane vesicle preparation containing Cl--ATPase from Aplysia foregut, it was shown that orthovanodate inhibited Cl--ATPase activity, ATP-dependent Cl- transport and ATP-dependent membrane potential change. N-ethylmalemide (NEM) and p-chloromercurobenzoate (PCMBS) also inhi bited the Cl- pump biochemical and transport characteristics. However, bafi lomycin, azide, DCCD or efrapeptin had no effect on the Cl- pump characteri stics suggesting that this Cl- pump was a P-type ATPase.