RESUMEN
In 1923 Karl H. Slotta obtained his PhD in chemistry from the University of Breslau, Germany, where he continued to work. At the instigation of the gynaecologist Ludwig Fraenkel, Slotta made the first isolation of progesterone in 1933. In 1934 he proposed the correct structural formula. Slotta was appointed professor of chemistry in 1935, but with the oppression of the Nazi regime mounting, he soon left Germany with his family to take a post at the Instituto Butantan, Brazil. Initially he worked on the chemistry of coffee. In 1938 Slotta and his brother-in-law Heinz Fraenkel-Conrat isolated crotoxin from Crotalus durissus terrificus venom, the first snake toxin to be obtained in crystalline form. They had evidence to suggest that the toxicity of crotoxin was due to a phospholipolytic action on nerve lipids. In 1938 Slotta's department was closed; he subsequently cofounded a biopharmaceutical company. In 1956 Slotta was appointed research professor of biochemistry at the University of Miami, USA. Slotta purified the most basic polypeptide from Naja naja venom, known as direct lytic factor, and with James Vick identified this as cardiotoxin. Karl H. Slotta will be remembered not only for his skill as a biochemist but also for his indomitable and cheerful spirit.
