:Intermediate cleaving peptidase 55

{{Short description|Class of enzymes}}

{{Infobox enzyme

| Name = Intermediate cleaving peptidase 55

| EC_number = 3.4.11.26

| CAS_number =

| GO_code =

| image =

| width =

| caption =

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Intermediate cleaving peptidase 55 ({{EC number|3.4.11.26}}, Icp55, mitochondrial intermediate cleaving peptidase 55 kDa) is an enzyme.{{cite journal | vauthors = Naamati A, Regev-Rudzki N, Galperin S, Lill R, Pines O | title = Dual targeting of Nfs1 and discovery of its novel processing enzyme, Icp55 | journal = The Journal of Biological Chemistry | volume = 284 | issue = 44 | pages = 30200–8 | date = October 2009 | pmid = 19720832 | pmc = 2781575 | doi = 10.1074/jbc.M109.034694 | doi-access = free }}{{cite journal | vauthors = Vögtle FN, Wortelkamp S, Zahedi RP, Becker D, Leidhold C, Gevaert K, Kellermann J, Voos W, Sickmann A, Pfanner N, Meisinger C | title = Global analysis of the mitochondrial N-proteome identifies a processing peptidase critical for protein stability | journal = Cell | volume = 139 | issue = 2 | pages = 428–39 | date = October 2009 | pmid = 19837041 | doi = 10.1016/j.cell.2009.07.045 | s2cid = 12789215 | doi-access = free }} This enzyme catalyses the following chemical reaction

: The enzyme cleaves the Pro36-Pro37 bond of cysteine desulfurase (EC 2.8.1.7) removing three amino acid residues (Tyr-Ser-Pro) from the N-terminus after cleavage by mitochondrial processing peptidase.

Icp55 removes the destabilizing N-terminal amino acid residues.