Source:http://linkedlifedata.com/resource/umls/id/C0086605
NCI: Form of Vitamin K containing a double-bond in all of its multiple isoprenoid side chains, usually numbering between 2 -13.,MSH: A group of substances similar to VITAMIN K 1 which contains a ring of 2-methyl-1,4-naphthoquinione and an isoprenoid side chain of varying number of isoprene units. In vitamin K 2, each isoprene unit contains a double bond. They are produced by bacteria including the normal intestinal flora.