Mitochondrial-processing peptidase subunit alpha (PMPCA or MPPA; MEROPS identifier M16.971) is a non-proteolytic component of the complex that removes the first transit peptide from the N terminus of proteins synthesized in the cytoplasm but destined for the mitochondrion. PMPCA is itself synthesized in the cytoplasm and has an N-terminal transit peptide. Mutations in PMPCA result in abnormal mitochondrial protein processing in patients with non-progressive cerebellar ataxia [].
