FRACTIONATION OF BOTHROPS-PIRAJAI SNAKE-VENOM - ISOLATION AND CHARACTERIZATION OF PIRATOXIN-I, A NEW MYOTOXIC PROTEIN

Whole desiccated venom of Bothrops pirajai was fractionated on a gel filtration (Sephadex G-75) column. Phospholipase A(2), arginine esterase and dotting activity profiles of the six fractions (SI to SVI) obtained were determined. Fraction SIV from the gel filtration column was subjected to chromatography on SP-Sephadex C-25. It was resolved into five subfractions (SIV-SP1 to SIV-SP5). Fractions SIV-SP1, SIV-SP2 and SIV-SP3 showed phospholipase A(2) activity but, among these fractions, only SIV-SP3 was homogeneous. Induction of myonecrosis by SIV-SP3, SIV-SP4 and SIV-SP5 was demonstrated by their ability to release serum creatine kinase, and for SIV-SP5, to induce histological alterations in the injected mouse muscle. Chemical characterization by determination of mof. wts, isoelectric focusing and direct manual sequencing of the N-terminal region was performed for SIV-SP3, SIV-SP4 and SIV-SP5. When compared with bothropstoxin-I, the myotoxin SIV-SP5 showed the same total number of amino acid residues (121) and constant molar ratio for all but three amino acids. We have named this toxin piratoxin-I (PrTX-I).