The mitochondrial inner membrane peptidase (IMP) complex generates mature, active proteins in the mitochondrial intermembrane space by proteolytically removing the mitochondrial targeting presequence of nuclear-encoded proteins. IMP1 and IMP2 (IMMP2L; MIM 605977) are the catalytic subunits of the IMP complex (Burri et al., 2005 [PubMed 15814844]).