Purification of a cytochrome aa3 terminal oxidase from protoplast membrane vesicles of Micrococcus luteus

Abstract A cytochrome aa 3 terminal oxidase was isolated from protoplast membrane vesicles of Micrococcus luteus grown under aerobic conditions. The purified complex showed similarities to cytochrome c oxidase (EC 1.9.3.1) of the electron transport chain of mitochondria and many prokaryotes. The enzyme was solubilized by subsequent treatment with the detergents CHAPS and n- dodecyl -β- d - maltoside and purified by ion-exchange chromatography using poly- l -lysine agarose and TMAE-fractogel-650 (S) columns, followed by hydroxyapatite chromatography. The purified complex is composed of two major subunits with apparent molecular masses of 54 and 32 kDa. After purification the isolated enzyme …