Cytochrome c oxidase (E.C:7.1.1.9) is a key enzyme in aerobic metabolism. Proton pumping haem-copper oxidases represent the terminal, energy-transfer enzymes of respiratory chains in prokaryotes and eukaryotes. The CuB-haem a3 (or haem o) binuclear centre, associated with the largest subunit I of cytochrome c and ubiquinol oxidases (E.C:1.10.3.11), is directly involved in the coupling between dioxygen reduction and proton pumping [1,2,3,4]. Some terminal oxidases generate a transmembrane proton gradient across the plasma membrane (prokaryotes) or the mitochondrial inner membrane (eukaryotes). The enzyme complex consists of 3-4 subunits (prokaryotes) up to 13 polypeptides (mammals) of which only the catalytic subunit (equivalent to mammalian subunit I (COXI) is found in all haem-copper respiratory oxidases. The presence of a bimetallic centre (formed by a high-spin haem and copper B) as well as a low-spin haem, both ligated to six conserved histidine residues near the outer side of four transmembrane spans within CO I is common to all family members [2,3]. [1]. 8638158. The whole structure of the 13-subunit oxidized cytochrome c. oxidase at 2.8 A.. Tsukihara T, Aoyama H, Yamashita E, Tomizaki T, Yamaguchi H,. Shinzawa-Itoh K, Nakashima R, Yaono R, Yoshikawa S;. Science 1996;272:1136-1144.. [2]. 8013452. Evolution of cytochrome oxidase, an enzyme older than. atmospheric oxygen.. Castresana J, Lubben M, Saraste M, Higgins DG;. EMBO J. 1994;13:2516-2525.. [3]. 31489376. Dimeric structures of quinol-dependent nitric oxide reductases. (qNORs) revealed by cryo-electron microscopy.. Gopalasingam CC, Johnson RM, Chiduza GN, Tosha T. TRUNCATED at 1650 bytes (from Pfam)
GO Terms:- Molecular Function:
- cytochrome-c oxidase activity (GO:0004129)
- Biological Process:
- aerobic respiration (GO:0009060)
- Cellular Component:
- membrane (GO:0016020)
- Molecular Function:
- heme binding (GO:0020037)
- Date:
- 2024-08-14