Blood-clotting Activity of the Venom of Bothrops jararaca

THE well-known blood-clotting activity of the venom from snakes of various species of the genus Bothrops has been attributed to its proteolytic activity 1 , although Michl 2 (using paper electrophoresis) and Holz and Raudonat 3 (using fractional precipitation with ammonium sulphate) have presented evidence against this point of view. The latter authors obtained a fraction, which they called “Koagulin”, with a strong blood-clotting activity but only slight proteolytic activity when hæmoglobin was used as substrate. More recently, it has been shown that there exist at least two proteolytic enzymes in the venom of Bothrops jararaca : one of them is thermolabile 4 and is precipitated at 50 per cent saturation with ammonium sulphate 5 , while the other is stable to heat 4 and is precipitated at 70 per cent saturation with ammonium sulphate 5 . The latter enzyme has been isolated in a fairly pure state and has been called Bothrops protease A (ref. 6).