Mitochondrial processing peptidase (MPP) is a soluble enzyme complex which cleaves N-terminal signal sequences from mitochondrial preproteins after translocation the double membrane. MPP can also cleave the N-terminal presequences followed by hydrophobic sorting signals in proteins localized in the inner membrane and intermembrane space. MMP is a dimeric complex, with an alpha subunit which binds the presequence and a catalytic beta subunit. (Adapted from PMID:22172993 and PMID:35185991.)