(phylloquinone, phytomenadione, phytonadione, menaquinone , ahemorrhage vitamin, coagulation vitamin)
Vitamin K was first discovered by H. Dam in Denmark during testing of cholesterol metabolism in chicks fed with food without lipids. Dam noticed bleeding skin and muscles, which were often accompanied with blood clotting. He stated that this is probably a disease caused by vitamin deficiency. Later, in 1935, E. A. Doisy and his associates isolated and determined the structure of this vitamin.
Edward A. Doisy, Nobel Prize in Medicine in 1943
(Image taken from Nobelprize.org )
It was the last detected and characterized vitamin that is soluble in fats.