The effect of vitamin K1 on oxidative phosphorylation of rat liver mitochondria irradiated with ultraviolet light.

Almost 20 years have elapsed since the isolation of vitamin K1 by Doisy et al. (1) and Dam et a?. (2); yet, there is still no adequate explanation for its action in animals. It has been recsognized for some time that. vitamin K is required for the synthesis of prothrombin (3, 4) but it has never been established whether this is a specific or nonspecific effect. It has been found that vitamin K1 is an essential part of the photosynthetic phosphorylation process in green plants (5). Martius and NitzLitzow (6, 7) have postulated that vitamin Kr plays a similar part in the animal world; i.e. that it is a necessary cofactor for osidative phosphorylation. In the work to be presented, the authors have taken advantage of the sensitivity of vitamin K to ultraviolet light (8) to substantiate and extend previous reports by Martius and NitzLitzow (6). Preliminary accounts of this work have appeared (9, 10).