COX5A
Protein-coding gene in the species Homo sapiens
From Wikipedia, the free encyclopedia
Cytochrome c oxidase subunit 5a is a protein that in humans is encoded by the COX5A gene. Cytochrome c oxidase 5A is a subunit of the cytochrome c oxidase complex, also known as Complex IV, the last enzyme in the mitochondrial electron transport chain.[5]
| COX5A | |||||||||||||||||||||||||||||||||||||||||||||||||||
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| Aliases | COX5A, COX, COX-VA, VA, cytochrome c oxidase subunit 5A, MC4DN20 | ||||||||||||||||||||||||||||||||||||||||||||||||||
| External IDs | OMIM: 603773; MGI: 88474; HomoloGene: 37905; GeneCards: COX5A; OMA:COX5A - orthologs | ||||||||||||||||||||||||||||||||||||||||||||||||||
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Structure
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.[5] The COX5A protein weighs 17 kDa and is composed of 150 amino acids.[6][7] The protein is a subunit of Complex IV, which consists of 13 mitochondrial- and nuclear-encoded subunits.[5]
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.[5]
Summary reaction:
- 4 Fe2+-cytochrome c + 8 H+in + O2 → 4 Fe3+-cytochrome c + 2 H2O + 4 H+out[8]
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.[9]
The Trans-activator of transcription protein (Tat) of human immunodeficiency virus (HIV) inhibits cytochrome c oxidase (COX) activity in permeabilized mitochondria isolated from both mouse and human liver, heart, and brain samples.[10]