PURIFICATION, PROPERTIES, AND N-TERMINAL AMINO-ACID-SEQUENCE OF A KALLIKREIN-LIKE ENZYME FROM THE VENOM OF LACHESIS-MUTA-RHOMBEATA (BUSHMASTER)

Pit viper venoms contain multiple proteinases which cause considerable damage in tissues and systemic effects after envenomation. A proteina se, kallikrein-like enzyme, belonging to the serine group must play a very important role on systemic effects. The corresponding enzyme from Lachesis muta rhombeata venom was purified to homogeneity by a combin ation of isoelectrofocusing fractionation followed by one step of gel filtration HPLC. The enzyme focused with pi 5.0-6.5, it had a molecula r mass of 32 kDa by gel filtration HPLC, had edematogenic activity, an d induced a hypotensic effect in anesthetized rats. It exhibited stron g N-alpha-tosyl-L-Arg methyl esterase (955.38 units/mg) and N-Bz-DL-Ar g-pNA amidolytic (233.02 units/mg) activities, hydrolyzed tripeptide n itroanilide derivatives weakly or not at all, and cleaved selectively the A-alpha and B-beta chains of fibrinogen, apparently leaving the Y- chain unaffected. The 30 N-terminal amino acid sequence of the L. m. r hombeata protein showed greatest identity (74% in 26 amino acids) with Crotalus viridis kallikrein-like protein, but significant similaritie s in sequence were observed with enzymes from other snake venoms and p ig pancreatic kallikrein.