The effect of ultraviolet light on mitochondria. II. Restoration of oxidative phosphorylation with vitamin K1 after near-ultraviolet treatment.

The demonstration by Martius and Nitz-Litzow (4), and Martius (5), that vitamin K1 may play a functional role in oxidative phosphorylation in animals has led to an increased interest in the participation of vitamin Ki and related quinones in electron transport, oxidative phosphorylation, and photosynthetic phosphorylation. Since vitamin K1 is altered by the action of ultraviolet radiation (6), we have treated rat liver mitochondria with near-ultraviolet light in order to alter such intramitochondrial components. After such treatment, oxidative phosphorylation with succinate as substrate is dependent upon the addition of cytochrome c, and oxidative phosphorylation with glutamate as substrate is dependent upon the addition of cytochrome c and vitamin K1. The action of vitamin K1 appears to be specific in that a number of related compounds do not restore oxidative phosphorylation.