THE REACTIVITY OF A NATURALLY OCCURRING QUINONE (Q-255) IN PHOTOCHEMICAL REACTIONS OF ISOLATED CHLOROPLASTS

Abstract

Lyophilized chloroplasts from sugar beet, spinach and swiss chard were extracted with petroleum ether and found to contain Q-255, a new benzoquinone. Q-255 is not only superior to vitamin K in its ability to reactivate photochemical activity in chloroplasts but is superior to the coenzyme Q compound (Q-275) isolated from mitochondria. The mole-ratio of Q-255 to chlorophyll was calculated to be a minimum of 0.12. The same substituted p-benzoquinone was extracted from a blue-green alga and from several green algae. It is theorized that Q-255 should be capable of most reactions tentatively assigned to vitamin K in the photosynthetic process; it is most probably a catalyst confined to the photosynthetic tissue.