A rapid method for the purification of monomeric and/or dimeric phospholipases A2 in crotalid snake venoms

We have developed a simple two-step procedure for the separation of monomeric (14,000 mol. wt) and dimeric (28,000 mol. wt) phospholipases A2 from the venoms of Crotalidae family snakes. All venom phospholipases A2 studied thus far exist as monomers under acidic conditions and are chromatographed as such on a column of G-50 Sephadex (superfine) equilibrated in 5% acetic acid. Separation of dimeric phospholipases A2 from any monomeric enzyme(s) in pools of enzyme thus obtained is achieved by chromatography on a second column of G-50 Sephadex (superfine) identical to the first but developed in 1% ammonium bicarbonate. This method has been applied to an investigation of the prevalence of monomeric and/or dimeric enzymes in venoms of the Crotalidae family. The distribution of monomeric and dimeric phospholipases correlates well with phylogeny. In the more primitive Crotalidae genera, such as Trimeresurus and Agkistrodon, monomeric phospholipases A2 are predominant. In the more highly evolved Crotalus genus, only dimeric enzymes are found.