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Updated: Jun 28, 2026

Mitochondrial Respiration Quantification in Yeast Whole Cells
Published on: November 8, 2024
Hydroxylation of demethoxy-Q6 constitutes a control point in yeast coenzyme Q6 biosynthesis
S Padilla1, U C Tran, M Jiménez-Hidalgo
1Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide-CSIC and Centre for Biomedical Research on Rare Diseases (CIBERER), Carretera de Utrera, km 1, ISCIII, 41013 Sevilla, Spain.
Abstract:
Coenzyme Q is a lipid molecule required for respiration and antioxidant protection. Q biosynthesis in Saccharomyces cerevisiae requires nine proteins (Coq1p-Coq9p). We demonstrate in this study that Q levels are modulated during growth by its conversion from demethoxy-Q (DMQ), a late intermediate. Similar conversion was produced when cells were subjected to oxidative stress conditions. Changes in Q(6)/DMQ(6) ratio were accompanied by changes in COQ7 gene mRNA levels encoding the protein responsible for the DMQ hydroxylation, the penultimate step in Q biosynthesis pathway. Yeast coq null mutant failed to accumulate any Q late biosynthetic intermediate. However, in coq7 mutants the addition of exogenous Q produces the DMQ synthesis. Similar effect was produced by over-expressing ABC1/COQ8. These results support the existence of a biosynthetic complex that allows the DMQ(6) accumulation and suggest that Coq7p is a control point for the Q biosynthesis regulation in yeast.
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