INTACT ALPHA-SUBUNIT IS REQUIRED FOR MEMBRANE-BINDING OF HUMAN MITOCHONDRIAL TRIFUNCTIONAL BETA-OXIDATION PROTEIN, BUT IS NOT NECESSARY FOR CONFERRING 3-KETOACYL-COA THIOLASE ACTIVITY TO THE BETA-SUBUNIT

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