part of mitochondrial matrix mitochondrial processing peptidase complex https://github.com/geneontology/go-ontology/issues/27929 GO:0017087 A protein complex consisting of a regulatory subunit (alpha-MPP) and a catalytic subunit (beta-MPP) that catalyzes the release of N-terminal targeting peptides from precursor proteins imported into the mitochondrion. Note that monomeric mitochondrial processing peptidases have been observed. cellular_component mitochondrial protein-containing complex endopeptidase complex