menaquinone

Etymology
From.

Noun

 * 1)  A pale yellow crystalline naphthoquinone C41H56O2 that is obtained especially from putrefied fish meal and produced by bacteria in the large intestine and essential for the blood-clotting process. It is much more unsaturated than vitamin K1 and slightly less active biologically, and is an isoprenoid derivative of menadione.

Synonyms

 * vitamin K2