Purification and characterization of a membrane-bound ATPase from Acetabularia cliftonii that corresponds to a Cl(-)-translocating ATPase in Acetabularia acetabulum.

A Mg(2+)-ATPase was solubilized from membranes of Acetabularia cliftonii using nonanoyl-N-methylgluconamide and purified by ion-exchange and gel permeation chromatography. One active ATPase fraction after Mono Q chromatography had a specific activity of 10 units/mg of protein. Judged from subunit composition [54 (a), 50 (b) with a fainter band around 40 kDa], catalytic properties, and N-terminal amino acid sequence of the b subunit, the isolated enzyme was comparable to the Cl(-)-ATPase of Acetabularia acetabulum. Immunological characterization of both subunits showed significant similarity to the F type of ATPase. Cl(-)-transport activity was observed by reconstitution studies into liposomes.