Reaction: The enzyme cleaves the Pro36-Pro37 bond of cysteine desulfurase (EC 188.8.131.52) removing three amino acid residues (Tyr-Ser-Pro) from the N-terminus after cleavage by mitochondrial processing peptidase.
Other name(s): Icp55; mitochondrial intermediate cleaving peptidase 55 kDa
Comments: Icp55 removes the destabilizing N-terminal amino acid residues that are left after cleavage by the mitochondrial processing peptidase, leading to the stabilisation of the substrate. The enzyme can remove single amino acids or a short peptide, as in the case of cysteine desulfurase (EC 184.108.40.206), where three amino acids are removed.
Links to other databases: BRENDA, EXPASY, KEGG, MEROPS, Metacyc, CAS registry number:
1. Naamati, A., Regev-Rudzki, N., Galperin, S., Lill, R. and Pines, O. Dual targeting of Nfs1 and discovery of its novel processing enzyme, Icp55. J. Biol. Chem. 284 (2009) 30200-30208. [PMID: 19720832]
2. Vogtle, F.N., Wortelkamp, S., Zahedi, R.P., Becker, D., Leidhold, C., Gevaert, K., Kellermann, J., Voos, W., Sickmann, A., Pfanner, N. and Meisinger, C. Global analysis of the mitochondrial N-proteome identifies a processing peptidase critical for protein stability. Cell 139 (2009) 428-439. [PMID: 19837041]