Biosynthesis of coenzyme Q in eukaryotes.

Coenzyme Q (CoQ) is a component of the electron transport chain that participates in aerobic cellular respiration to produce ATP. In addition, CoQ acts as an electron acceptor in several enzymatic reactions involving oxidation–reduction. Biosynthesis of CoQ has been investigated mainly inEscherichia coliandSaccharomyces cerevisiae, and the findings have been extended to various higher organisms, including plants and humans. Analyses in yeast have contributed greatly to current understanding of human diseases related to CoQ biosynthesis. To date, human genetic disorders related to mutations in eightCOQbiosynthetic genes have been reported. In addition, the crystal structures of a number of proteins involved in CoQ synthesis have been solved, including those of IspB, UbiA, UbiD, UbiX, UbiI, Alr8543 (Coq4 homolog), Coq5, ADCK3, and COQ9. Over the last decade, knowledge of CoQ biosynthesis has accumulated, and striking advances in related human genetic disorders and the crystal structure of proteins required for CoQ synthesis have been made. This review focuses on the biosynthesis of CoQ in eukaryotes, with some comparisons to the process in prokaryotes. The enzymes involved in CoQ synthesis form a complex inS. cerevisiae. At least nine peptides are required for the synthesis of CoQ. [ABSTRACT FROM PUBLISHER]