A QUICK PROCEDURE FOR THE ISOLATION OF DIMERIC PIRATOXIN-I AND PIRATOXIN-II, 2 MYOTOXINS FROM BOTHROPS-PIRAJAI SNAKE-VENOM - N-TERMINAL SEQUENCING

Two myotoxins, MP-I and MP-II, from Bothrops pirajai snake venom, have been purified by a quick high performance liquid chromatography (HPLC ) procedure. Based on the HPLC coelution profile, amino acid compositi on, N-terminal sequence, polyacrylamide gel electrophoresis (PAGE) mig ration, as well as lack of phospholipase-A(2) (PLA(2)) and proteolytic activities, MP-I and MP-II were identified as piratoxin-I (PrTX-I) an d II (PrTX-II), respectively. This procedure affords, aside the reduce d operation time, a high yield (35% of the applied sample in terms of A(280nm)) Of MP-I, which is the major myotoxin of the venom. The N-ter minal sequences of MP-I, MP-II, PrTX-I and PrTX-II, up to the 51st, 31 st, 46th and 39th residues, respectively, have been determined, reveal ing MP-I (and hence PrTX-I) as a Lys-49 PLA(2)-like myotoxin. Both MP- I and MP-II have been shown, by SDS-PAGE, to occur in dimeric isoforms .