Respiratory ubiquinone-9 from Hyphomicrobium spec. Strain ZV 580

Ubiquinone-9, an ubiquinone with a side-chain containing 9 prenyl residues, was purified from Hyphomicrobium spec. strain ZV 580, and identified by thin-layer chromatography, UV spectroscopy, and mass spectrometry. The participation of the quinone in the reactions of the respiratory chain was established by observing its increasing reduction in a membrane fraction upon the addition of NADH, the exhaustion of oxygen, and in the presence of NADH plus cyanide. The degrees of reduction in these states matched those of the cytochromes b and c.