The phospholipids associated with cytochrome c oxidase isolated from beef, dogfish and cod heart.

Beef (Bos taurus), dogfish (Squalus acanthias) and cod (Gadus morhua) heart submitochondrial particles and cytochrome c oxidase (EC 1.9.3.1) were prepared. The head groups and side chains of the phospholipids associated with these samples were analysed quantitatively. The fish phospholipids contained a higher proportion of long chain poly-unsaturated fatty acids than was found in the beef samples. The enzyme fraction showed no head group or fatty acyl chain preference when compared with the composition of the whole tissue, implying no special lipid requirement for enzyme activity other than membrane fluidity. No cardiolipin was associated with the dogfish oxidase. The cod oxidase was inseparable from a CO-binding "b-type" cytochrome.