JBC, Vol. 251, Issue 23, 7343-7347, Dec, 1976
Isolation and amino acid sequence of a neurotoxic phospholipase A from the venom of the Australian tiger snake Notechis scutatus scutatus
J. Halpert and D. Eaker
The complete amino acid sequence of notechis 5, a neurotoxic phospholipase
A from the venom of Notechis scutatus scutatus (Australian tiger snake),
has been elucidated. The main fragmentation of the 119-residue peptide
chain was accomplished by digesting the reduced and S-carboxymethylated
derivative of the protein with a staphylococcal protease specific for
glutamoyl bonds. Tryptic peptides were used to align and complete the
sequence of the four staphylococcal protease peptides. The sequence was
determined by Edman degradation by means of the direct phenylthiohydantoin
method. Notechis 5 differs in seven positions from the recently elucidated
sequence of the presynaptic neurotoxin notexin from the same venom.
Notechis 5 has a 50% higher specific prospholipase A activity than notexin
when assayed against egg yolk but is only one-third as toxic.