Open AccessUbiquinone biosynthesis in microorganisms
Author(s) -
Meganathan R
Publication year - 2001
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2001.tb10831.x
Subject(s) - shikimate pathway , biochemistry , mevalonate pathway , biosynthesis , saccharomyces cerevisiae , prenylation , hydroxybenzoate , aromatic amino acids , yeast , decarboxylation , escherichia coli , tyrosine , biology , chemistry , stereochemistry , amino acid , enzyme , gene , catalysis
The quinoid nucleus of the benzoquinone, ubiquinone (coenzyme Q; Q), is derived from the shikimate pathway in bacteria and eukaryotic microorganisms. Ubiquinone is not considered a vitamin since mammals synthesize it from the essential amino acid tyrosine. Escherichia coli and other Gram‐negative bacteria derive the 4‐hydroxybenzoate required for the biosynthesis of Q directly from chorismate. The yeast, Saccharomyces cerevisiae , can either form 4‐hydroxybenzoate from chorismate or tyrosine. However, unlike mammals, S. cerevisiae synthesizes tyrosine in vivo by the shikimate pathway. While the reactions of the pathway leading from 4‐hydroxybenzoate to Q are the same in both organisms the order in which they occur differs. The 4‐hydroxybenzoate undergoes a prenylation, a decarboxylation and three hydroxylations alternating with three methylation reactions, resulting in the formation of Q. The methyl groups for the methylation reactions are derived from S ‐adenosylmethionine. While the prenyl side chain is formed by the 2‐ C ‐methyl‐ d ‐erythritol 4‐phosphate (non‐mevalonate) pathway in E. coli , it is formed by the mevalonate pathway in the yeast.