Indispensability of Ubiquinone in the Aerobic Respiratory Chain of Photobacterium phosphoreum(Biological)

概要

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Quinones contained in the membrane of Photobacterium phosphoreum grown aerobically were studied. Ubiquinone-8 (Q-8), menaquinone-8 (MK-8), and demethylmenaquinone-8 (DMK-8) were identified by mass spectroscopy. To establish the function of the quinones in the aerobic respiratory chain, depletion and reincorporation experiments were performed. Quinones were removed efficiency by n-pentane-acetone (9 : 1, v/v) extraction. The depleted membrane showed no reduced nicotinamide adenine dinucleotide (NADH) oxidase activity and yet retained NADH dehydrogenase activity and ubiquinol-1 (Q_1H_2) oxidase activity. When Q-8 was reincorporated into quinone-depleted membrane vesicles by a freeze-thawsonication method, the NADH oxidase activity was restored completely. However, the other quinones contained in P. phosphoreum (MK-8 and DMK-8) did not have the ability to restore the activity of NADH oxidase. The Q_1H_2 oxidase or NADH dehydrogenase activity did not alter with the addition of the three kinds of quinones. These results suggest that Q-8 is a component of the aerobic respiratory chain of P. phosphoreum.
社団法人日本薬学会の論文
1987-04-25