vitamin-k-semiquinone-radical and 2-3-dimethoxy-5-methyl-6-decyl-1-4-benzoquinone

Decyl-ubiquinone and decyl-plastoquinone were used as model compounds to test the potential effect of quinone derivatives on two enzymes of the vitamin K cycle in vitro. Substantial inhibition of gamma-glutamate carboxylase was found, whereas vitamin K-epoxide reductase was inhibited to a much lesser extent. The inhibitory effect of both decylquinones was eliminated in a time-dependent way by solubilized microsomes, but not by purified carboxylase. Since a wide variety of prenylquinones occur as micronutrients, these results are of potential relevance for the effects of natural quinones in the human diet.

Topics: Animals; Carbon-Carbon Ligases; Cattle; Kinetics; Ligases; Liver; Microsomes, Liver; Mixed Function Oxygenases; Plastoquinone; Ubiquinone; Vitamin K; Vitamin K Epoxide Reductases