Kinya Uchida

Incorporation of molecular oxygen during the biosynthesis of ubiquinone in an aerobic bacterium, Pseudomonas desmolytica

Abstract By using 18O2, it was shown that two atoms from atomospheric oxygen are incorporated into a ubiquinone-9 molecule during biosynthesis by Pseudomonas desmolytica . Separate chemical experiments proved that both oxygen atoms in carbonyl groups of the ubiquinone molecule will exchange with water, while the two 18O atoms incorporated do not, in 0.2N HCl at 85°C. These experiments lead to the conclusion that the molecular oxygens are incorporated into two methoxy groups linked to C-5, 6 of the quinone ring. The importance of the cooperative relationship between respiratory system and oxygenation system in oxygen metabolism of bacteria is emphasized.