Amino acid sequence of a cytotoxin-like basic protein with low cytotoxic activity from the venom of the Thailand cobra Naja naja siamensis.

A cytotoxin-like basic protein (CLBP) was isolated from the venom of the Thailand cobra (Naja naja siamensis). The cytotoxicity of CLBP toward FL cells was one order of magnitude lower than those of cytotoxins. The amino acid sequence was determined by a combination of conventional methods. The total number of amino acid residues was 62, giving a molecular mass of 6977 Da. The sequence at residues 25-30 in the CLBP molecule was found to be significantly different from those of cytotoxins. This region might play an important role in the cytotoxic activity of cytotoxins.