Menaquinones are isoprenoid quinones of the naphthalene series and belongs to the K2 Vitamin homologs. Menaquinones were originally discovered as the anti-hemorrhagic factor and now encompasses a variety of physiological processes. Menaquinone-6 were the major isoprenoid quinones found in membrane preparations of Campylobacter jejuni and Campylobacter fetus.
Vitamin (prothrombogenic).
Menaquinone 6 plays an essential role as an electron carrier in the bacterial respiratory chain. Only small amounts of menaquinone 6 can be found in human.