Vitamin K [Chemical/Ingredient] Vitamin K Vitamin K M0022806 D014812 C0042878 A lipid cofactor that is required for normal blood clotting. Several forms of vitamin K have been identified: VITAMIN K 1 (phytomenadione) derived from plants, VITAMIN K 2 (menaquinone) from bacteria, and synthetic naphthoquinone provitamins, VITAMIN K 3 (menadione). Vitamin K 3 provitamins, after being alkylated in vivo, exhibit the antifibrinolytic activity of vitamin K. Green leafy vegetables, liver, cheese, butter, and egg yolk are good sources of vitamin K. 11258 N0000006290 C22926 Vitamin K Naphthoquinones [Chemical/Ingredient] Phytol [Chemical/Ingredient]