Amino acid sequence of phospholipase A from Bungarus multicinctus venom.

Bungarus multicinctus phospholipase A was reduced and carboxymethylated. The RCM-enzyme was digested with TPCK-trypsin or cleaved with cyanogen bromide followed by chymotrypsin digestion. The resulting peptide mixtures were fractionated by gel filtration on Sephadex G-50 and G-25 columns or by DEAE-cellulose (DE-32) column chromatography. Further purification of the peptide mixtures was performed by paper electrophoresis at pH 3.5 or 6.5 or by paper chromatography. The sequences of isolated peptides were determined by the manual Edman or dansyl-Edman method. From the sequences of these peptides the whole enzyme sequence (total 118 residues) was deduced. The complete sequence of the enzyme is similar to those of phospholipases A2 from other snake venoms and mammalian pancreas. Further, a 58% sequence homology was found between the present phospholipase A and the A chain of beta 1-bungarotoxin, a presynaptic neurotoxin having weak phospholipase A activity, contained in the same venom.