VERY-LONG-CHAIN ACYL-COA DEHYDROGENASE SUBUNIT ASSEMBLES TO THE DIMERFORM ON MITOCHONDRIAL INNER MEMBRANE

This paper describes the process of dimer assembly of mitochondrial ve ry-long-chain acyl-CoA dehydrogenase (VLCAD) subunit. Mature VLCAD is a homodimer of a 70-kDa protein associated with the mitochondrial memb rane. Newly synthesized VLCAD was present as a monomer and the major f raction was associated with the mitochondrial inner membrane. The asso ciation of VLCAD subunit with the mitochondrial membrane was observed early during dimer formation. In contrast, a VLCAD monomeric mutant S5 83W, a novel mutation identified from a patient with VLCAD deficiency, did not associate with the mitochondrial membrane after import and th e major fraction remained in the mitochondrial matrix. These results s uggest that association of VLCAD protein with mitochondrial inner memb rane is necessary for dimer assembly and formation of mature VLCAD. (C ) 1998 Federation of European Biochemical Societies.