Purification and characterization of a fibrinogenase from Vipera lebetina (desert adder) venom
Résumé
A fibrinogenase from Vipera lebetina venom was isolated by gel filtration in a Superose 12 column prep grade HR 16/50 and by ion-exchange in a Mono Q HR 5/5 column. The purified enzyme, which was obtained with a yield of 8 mg from 60 mg of crude venom, is a glycoprotein having an isoelectric point of 5.9±0.1 and a mol. wt of 26,000±1000 as estimated by SDS-PAGE. The biochemical characterization of the enzyme revealed that it hydrolyzes readily the Bβ chain of fibrinogen and the Aα chain as well as fibrin and casein. Over a pH range from 4 to 11 the enzyme was not inactivated by a 20 min treatment at 90°C. The isolated fibrinogenase is inhibited by ethylenediamine tetraacetic acid, dithiothreitol and l-cysteine but not by phenylmethylsulfonyl fluoride. On the other hand, it is activated by Ca2+ and Mg2+. Purified fibrinogenase up to a dose of 100 μg/mouse shows no toxicity and has no hemorrhagic activity.