Oxidative phosphorylation in fractionated bacterial systems. XXII. The effect of near ultraviolet irradiation on the succinate oxidase pathway of Mycobacterium phlei.

The succinate oxidase activity of Mycobacterium phlei was sensitive to irradiation with light at 360 mp. The loss of activity was due to a lesion occurring in the electron transport chain between the flavoprotein and cytochrome b regions. The activity lost was not restored by addition of vitamin Kr or other cofactors but could be restored by the addition of the supernatant fraction. The factor responsible for the restoration of the succinate chain has been purified. It was sensitive to heat and irradiation and appeared to be protein in nature. It activated both oxidation and phosphorylation in irradiated particulate systems. The proteins which restored the two activities could not be separated.