UQCR11

The UQCR11 gene, located on the p arm of chromosome 19 in position 13.3, is made up of 3 exons and is 8,329 base pairs in length.^[6] The UQCR11 protein weighs 6.6 kDa and is composed of 56 amino acids.^[7][8] This gene encodes the smallest known component of the ubiquinol-cytochrome c reductase complex, which is also known as Complex III and is part of the mitochondrial respiratory chain.^[6] In vertebrates, Complex III contains 11 sub-units: 3 respiratory sub-units, 2 core proteins and 6 low-molecular weight proteins.^[9][10] Proteobacterial complexes may contain as few as three sub-units.^[11]

The UQCR11 protein may function as a binding factor for the iron-sulfur protein in Complex III, which is ubiquitous in human cells.^[6] Complex III catalyzes the chemical reaction

QH₂ + 2 ferricytochrome c ${\displaystyle \rightleftharpoons }$ Q + 2 ferrocytochrome c + 2 H⁺

Thus, the two substrates of Complex III are dihydroquinone (QH2) and ferri- (Fe³⁺) cytochrome c, whereas its 3 products are quinone (Q), ferro- (Fe²⁺) cytochrome c, and H⁺. This complex belongs to the family of oxidoreductases, specifically those acting on diphenols and related substances as donor with a cytochrome as acceptor. This enzyme participates in oxidative phosphorylation. It has four cofactors: cytochrome c₁, cytochrome b-562, cytochrome b-566 and a 2-Iron ferredoxin of the Rieske type.

This article incorporates text from the United States National Library of Medicine, which is in the public domain.