Cleavage of Trimeresurus flavoviridis phospholipase A2 with cyanogen bromide: sequence of the short peptide fragment and formation of a noncovalently bonded complex from the fragments.

Phospholipase A2 from the venom of Trimeresurus flavoviridis (Habu snake) on treatment with cyanogen bromide is split into less than Glu-Gly-Leu-Trp-Gln-Phe-Asn-Hse greater than, which is derived from the N-terminal moiety and is designated as S-peptide, and the remaining large peptide, which is designated as L-peptide. It should be stressed that the N-terminal residue is pyroglutamyl, unlike other phospholipases A2. The L-peptide alone was about 6% as active as the parent molecule. It occurs in dimeric form, like the parent molecule. When L-peptide was mixed with increasing amounts of S-peptide, the activity increased in a hyperbolic manner, indicating the formation of an ordered complex between L-peptide and S-peptide. The dissociation constant of the complex was 2.1 x 10(-7) M and its specific activity was 2.8 times that of L-peptide.