The strategy of using chemical modifications in the study of the role of various amino acids in the toxicity of venom PLA2s was also employed by other groups. The concepts that emanated from the work of Rosenberg and others were then incorporated into the hypothesis of Kini and Evans (1989) which proposed that toxic PLA2s interact with target proteins to induce their pharmacological effects, and were followed by the structural and mutagenesis studies that identified ‘toxic’ sites in venom PLA2s of various origins (Lomonte et al., 1994; Ivanovski et al., 2000; Ward et al., 2002).