Purification, some properties of two phospholipases A2 (CM-I and CM-II) and the amino-acid sequence of CM-II from Aspidelaps scutatus (shield or shield-nose) venom

Two phospholipases A2, CM-I and CM-II, from Aspidelaps scutatus venom were purified by gel filtration followed by ion-exchange chromatography on CM-cellulose. The enzymes consist of 119 amino acids including fourteen half-cystines. The complete primary structure of CM-II has been determined. The sequence and the invariant amino acid residues resemble those of the phospholipase A2 from the genus Naja. The toxicity of the enzymes is comparable to those encountered for the phospholipases A2 from African cobra venoms. The phospholipase A2 (CM-II) contains two histidine residues which are located at position 20 and the reactive site (histidine-47) of the enzyme.