Purification and partial characterization of an arginine ester hydrolase from the venom of the bushmaster snake, Lachesis muta noctivaga.

An arginine esterase was purified from the venom of Lachesis muta noctivaga by gel filtration on Sephadex G-100 and by affinity and DEAE cellulose chromatography. The purified enzyme preparation had an arginyl esterase specific activity of 181 mumoles/min/mg, which was 10.9-fold higher than the esterase activity found in the crude venom. The enzyme is free of kinin-releasing activity (kininogenase) and thrombin-like activity (fibrinogenase). The purified fraction showed a single band on polyacrylamide gel electrophoresis. The Km for Bz-L-Arg-O-Et is 1.14 X 10(-3)M, Vm 181.7 mumoles/min/mg and Kcat 90.9 sec-1. The pH profile indicates that the enzyme has an active region centered at pH 8.1. L. muta noctivaga arginyl esterase is reversibly inhibited by benzamidine (Ki 8.9 X 10(-4)M) and irreversibly inhibited by diisopropyl fluorophosphate.