Biosynthesis occurs in most human tissue. There are three major steps:
# Creation of the benzoquinone structure (using phenylalanine or tyrosine, via 4-hydroxybenzoate)
# Creation of the isoprene side chain (using acetyl-CoA)
# The joining or condensation of the above two structures
The initial two reactions occur in mitochondria, the endoplasmic reticulum, and peroxisomes, indicating multiple sites of synthesis in animal cells.
An important enzyme in this pathway is HMG-CoA reductase, usually a target for intervention in cardiovascular complications. The "statin" family of cholesterol-reducing medications inhibits HMG-CoA reductase. One possible side effect of statins is decreased production of CoQ, which may be connected to the development of myopathy and rhabdomyolysis. However, the role statins play in CoQ deficiency is controversial. Although statins reduce blood levels of CoQ, studies on the effects of muscle levels of CoQ are yet to come. CoQ supplementation also does not reduce side effects of statin medications.
Genes involved include PDSS1, PDSS2, COQ2, and ADCK3 (COQ8, CABC1).
Organisms other than humans produce the benzoquinone and isoprene structures from somewhat different source chemicals. For example, the bacteria E. coli produces the former from chorismate and the latter from a non-mevalonate source. The common yeast S. cerevisiae, however, derives the former from either chorismate or tyrosine and the latter from mevalonate. Most organisms share the common 4-hydroxybenzoate intermediate, yet again uses different steps to arrive at the "Q" structure.