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 f iltration (Sephadex G-75) column. Phospholipase A(2), arginine esteras e and dotting activity profiles of the six fractions (SI to SVI) obtai ned were determined. Fraction SIV from the gel filtration column was s ubjected to chromatography on SP-Sephadex C-25. It was resolved into f ive 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, SI V-SP4 and SIV-SP5 was demonstrated by their ability to release serum c reatine 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. Whe n 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).