Edward Adelbert Doisy was an American biochemist isolate and synthesize Vitamin K, used in medicine and surgery, a substance that encourages blood clotting (1939). For this work he was awarded Nobel Prize along with Henrik Dam in 1943
He developed assay techniques along with embryologist Edgar Allen. This facilitated research on sex hormones.
Doisy and his associates isolated the sex hormones estrone (theelin – the first estrogen to be crystallized), estriol (theelol), and estradiol (dihydrotheelin).
In 1936-39 he isolated two forms of the vitamin, K1 from lucerne seed and K2 from fish meal, in a pure crystalline form
