A comparison between vitamin K-dependent carboxylase from normal and warfarin-treated cows.

Detergent-solubilized microsomal preparations that catalyse the vitamin K-dependent gamma-carboxylation of glutamic acid residues in peptide and protein substrates, have been obtained from the livers of normal and warfarin-treated cows. The preparations from warfarin-treated animals contained more endogenous substrate than those from normal cows, but otherwise the two preparations were indistinguishable. The enzymes vitamin K reductase and gamma-glutamyl carboxylase, may function independently of each other in this system. They are, nevertheless, intimately linked in some way, so that the reduced vitamin K that is produced by the former enzyme can be used immediately by the latter.