The COX5A gene, located on the q arm of chromosome 15 in position 24.1, is made up of 5 exons and is 17,880 base pairs in length.[1] The COX5A protein weighs 17 kDa and is composed of 150 amino acids.[2][3] The protein is a subunit of Complex IV, which consists of 13 mitochondrial- and nuclear-encoded subunits.[1]
Function
Cytochrome c oxidase (COX) is the terminal enzyme of the mitochondrial respiratory chain. It is a multi-subunit enzyme complex that couples the transfer of electrons from cytochrome c to molecular oxygen and contributes to a proton electrochemical gradient across the inner mitochondrial membrane to drive ATP synthesis via protonmotive force. The mitochondrially-encoded subunits perform the electron transfer of proton pumping activities. The functions of the nuclear-encoded subunits are unknown but they may play a role in the regulation and assembly of the complex.[1]
Summary reaction:
4 Fe2+-cytochrome c + 8 H+in + O2 → 4 Fe3+-cytochrome c + 2 H2O + 4 H+out[4]
Clinical significance
COX5A (this gene) and COX5B are involved in the regulation of cancer cell metabolism by Bcl-2. COX5A interacts specifically with Bcl-2, but not with other members of the Bcl-2 family, such as Bcl-xL, Bax or Bak.[5]
↑Voet D, Voet JG, Pratt CW (2013). "Chapter 18". Fundamentals of biochemistry: life at the molecular level (4th ed.). Hoboken, NJ: Wiley. pp. 581–620. ISBN978-0-470-54784-7.
↑Chen ZX, Pervaiz S (Mar 2010). "Involvement of cytochrome c oxidase subunits Va and Vb in the regulation of cancer cell metabolism by Bcl-2". Cell Death and Differentiation. 17 (3): 408–20. doi:10.1038/cdd.2009.132. PMID19834492.
Williams SL, Valnot I, Rustin P, Taanman JW (Feb 2004). "Cytochrome c oxidase subassemblies in fibroblast cultures from patients carrying mutations in COX10, SCO1, or SURF1". The Journal of Biological Chemistry. 279 (9): 7462–9. doi:10.1074/jbc.M309232200. PMID14607829.
Kovalyov LI, Shishkin SS, Efimochkin AS, Kovalyova MA, Ershova ES, Egorov TA, Musalyamov AK (Jul 1995). "The major protein expression profile and two-dimensional protein database of human heart". Electrophoresis. 16 (7): 1160–9. doi:10.1002/elps.11501601192. PMID7498159.
Hofmann S, Lichtner P, Schuffenhauer S, Gerbitz KD, Meitinger T (1998). "Assignment of the human genes coding for cytochrome c oxidase subunits Va (COX5A), VIc (COX6C) and VIIc (COX7C) to chromosome bands 15q25, 8q22-->q23 and 5q14 and of three pseudogenes (COX5AP1, COX6CP1, COX7CP1) to 14q22, 16p12 and 13q14-->q21 by FISH and radiation hybrid mapping". Cytogenetics and Cell Genetics. 83 (3–4): 226–7. doi:10.1159/000015185. PMID10072584.
Rizzuto R, Nakase H, Zeviani M, DiMauro S, Schon EA (Sep 1988). "Subunit Va of human and bovine cytochrome c oxidase is highly conserved". Gene. 69 (2): 245–56. doi:10.1016/0378-1119(88)90435-0. PMID2853101.