Intact α-subunit is required for membrane-binding of human mitochondrial trifunctional β-oxidation protein, but is not necessary for conferring 3-ketoacyl-CoA thiolase activity to the β-subunit

Abstract

We have studied the activities of α and β subunit enzymes of the β-oxidation trifunctional protein complex in a patient who does not process the α-subunit. Long-chain 3-ketoacyl-CoA thiolase, the β-subunit enzyme, was transported into the mitochondrial matrix, where it expressed normal levels of activity, but was not translocated to the membrane. Thus, intact α-subunit is required for trifunctional protein membrane translocation, but is not necessary for conferring activity of the β-subunit. © 1995 Academic Press, Inc.