<p>The ubiquinol-cytochrome C reductase complex (cytochrome bc1 complex) is a respiratory multi-enzyme complex [<cite idref="PUB00006415"/>], which recognises a mitochondrial targeting presequence. The bc1 complex contains 11 subunits: 3 respiratory subunits (cytochrome b, cytochrome c1 and Rieske protein), 2 core proteins and 6 low molecular weight proteins. This family represents the 9.5 kDa subunit of the complex. This subunit together with cytochrome B binds to ubiquinone.</p>