Abstract
The rate of peroxide formation in the liver homogenate during the incubation was found to decrease by the addition of vitamin K_1. This effect was not observed under the variety of peroxide forming conditions in the absence of tissue. Vitamin K_1 was reduced by the NADH-K_1 reductase which was present in the soluble fractionn of liver and the reduced form of K_1 acted as a free radical traping substance. Dicoumarol, the specific inhibitor of the reductase, inhibited the protective effect of K_1 on the lipid peroxidation. These evidences suggest that vitamin K acts as an antioxidant under the physiological condition.
