High-resolution two-part basic urea gels for analysis of venom phospholipase A2 isoforms.

The performance of acidic and basic urea polyacrylamide gels has been improved by adopting a two-part gel system with a concentration discontinuity to act as a stacking boundary and by increasing the urea concentration to 8 M. The contributions of primary amino-group and guanidino-group ionizations to mobility have been evaluated by acetylation and phenyl glyoxal treatment respectively. The chromogenic PLA2 detection method of Shier and Trotter (Analyt. Biochem. 87, 604, 1978) has been modified for use with basic urea PAGE. The results have confirmed the major findings of other workers, but have demonstrated the presence of many hitherto uncharacterised isoforms of PLA2 in a variety of whole snake venoms. The basic urea PAGE (BG) method is proposed as the basis of a simple and rapid method for the classification of PLA2 isoforms which should allow unambiguous identification of isoforms by referring bands for purified material to the isoform content of whole venoms.