PURIFICATION AND CHARACTERIZATION OF A MEMBRANE-BOUND ATPASE FROM ACETABULARIA-CLIFTONII THAT CORRESPONDS TO A CL--TRANSLOCATING ATPASE IN ACETABULARIA-ACETABULUM

A Mg2+-ATPase was solubilized from membranes of Acetabularia cliftonii using nonanoyl-N-methylgluconamide and purified by ion-exchange and g el permeation chromatography. One active ATPase fraction after Mono Q chromatography had a specific activity of 10 units/mg of protein. Judg ed 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 subun its showed significant similarity to the F type of ATPase. Cl--transpo rt activity was observed by reconstitution studies into liposomes.