Vitamin K2 belongs to the naphthoquinone compounds. It can be divided into various subtypes according to the number of isoprene units in its side chain. Common subtypes include MK - 4 and MK - 7. The side chain of MK - 4 contains 4 isoprene units, while MK - 7 contains 7 isoprene units. Different subtypes have certain differences in biological activity and in - vivo metabolism.
