Purification of three arginine esterases from the venom of the Western Diamondback rattlesnake (Crotalus atrox)

—Three acidic arginine esterases have been isolated from the venom of the Western Diamondback rattlesnake (Crotalus atrox). These components demonstrated marked differences in ionic characteristics, as noted by KCl gradient elution from a DEAE-Sephadex A-50 column. Molecular weights, as determined from gel permeation chromatography, were estimated at 25,100 (fraction D), 24,000 (B); and 22,900 (F) for the three separate enzymes. The two larger enzymes (B and D) exhibited similar activities toward the synthetic substrates α-N-benzoyl-l-arginine ethyl ester and α-N-benzoyl-dl-arginine-p-nitroanilid Hydrolysis rates were similar to commercial trypsin preparations. Fraction F exhibited a markedly lower activity as an arginine esterase and negligible activity as an arginine amidase. Arginine esterase activity was evident for all three enzymes in the presence of ethylenediamine tetra-acetic acid.