1893-1986

American biochemist known for his isolation and synthesis of vitamin K, as well as his research on sex hormones. In 1939 Doisy isolated pure Vitamin K, which expedites blood clotting, from natural sources and figured out a way to produce K-1 synthetically. He also isolated the sex hormones estrone, estriol, and estradiol. In 1943 he was awarded the Nobel Prize for Physiology or Medicine, which he shared with Henrik Dam.