Coenzyme Q5, methyltransferase (COQ5)

Coenzyme Q5, methyltransferase (COQ5) is a SAM-dependent methyltransferase enzyme located in the mitochondrial matrix, essential for the biosynthesis of ubiquinone (coenzyme Q10), a critical component of the mitochondrial electron transport chain responsible for ATP generation. COQ5 catalyzes the C-methylation of 2-decaprenyl-6-methoxy-1,4-benzoquinol (DDMQH2) to 2-decaprenyl-3-methyl-6-methoxy-1,4-benzoquinol (DMQH2), thus facilitating one of the final steps in the production of coenzyme Q10. Mutations in COQ5 can cause primary coenzyme Q10 deficiency leading to severe neurodevelopmental, neurological, and multi-organ dysfunctions. COQ5 is considered a core component of the multi-enzyme CoQ-synthome complex essential for mitochondrial metabolism, and its loss or dysfunction leads to marked biochemical and physiological defects.

Other names

2-methoxy-6-polyprenyl-1,4-benzoquinol methylase, mitochondrialUbiquinone biosynthesis methyltransferase COQ5MGC47672-methoxy-6-polyprenyl-1,4-benzoquinol methylaseCOQ10D9COQ5 homolog, methyltransferase

Drugs that alter COQ5 would affect coenzyme Q10 biosynthesis by inhibiting or modulating methyltransferase activity during the conversion of intermediate benzoquinol substrates in the mitochondrial electron transport chain. (No direct drugs are reported in the sources.)