A PHOSPHOLIPID-DEPENDENT NADH-COENZYME-Q REDUCTASE FROM LIVER PLASMA-MEMBRANE

A 34 kDa coenzyme Q reductase has been solubilized and purified from p ig liver plasma membranes. The solubilized enzyme reduced coenzyme Q(0 ) with NADH. Ubiquinones with longer isoprenoid side chain such as Q(2 ) and Q(10) were also reduced when the quinones and the enzyme were re constituted into phospholipid liposomes. N-terminal sequencing of an i nternal peptide showed identity to bovine NADH-cytochrome b(5) reducta se. Biochemical characterization of the purified enzyme indicated that the coenzyme Q reductase corresponds to an unusual form of NADH-cytoc hrome bg reductase. (C) 1995 Academic Press, Inc.