Variation in the Protein Composition and Biological Activity of King Cobra (Ophiophagus hannah) Venoms

The biochemical properties and biological activities of the venom from three individual Ophiophagus hannah (King cobra) specimens was compared. The toxicity against mice, the cytotoxicity against five cell lines, and the antioxidant activity were measured. The KV2 venom showed a higher cytotoxicity than the KV6 and the non-cytotoxic KV9 venoms. Comparative analysis of the O. hannah venom proteins was performed after 2-dimensional (2-D) denaturing gel electrophoresis and reverse phase high performance liquid chromatography (RP-HPLC). 2-D analysis by isoelectric focusing (IEF) Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) resolution of the venoms revealed significant differences between all three venoms, with most spots being unique to that venom. Only 2 out of the 13-16 distinct spots were common to all three venoms, and four spots were common to KV6 and KV9. KV2 had the highest proportion of low molecular mass spots, and KV6 and KV9 appeared more related to each other than to KV9. From peptide mass mapping by matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and MASCOT-based amino acid sequence database searching, the two venom proteins that were common to all three specimens are likely to be ophanin and acidic phospholipase A₂ (PLA₂), whilst the proteins unique to the cytotoxic KV2 venom, included three other PLA₂ proteins. The RP-HPLC pattern of KV2 was different from the other two venoms with a higher protein concentration eluting in the 31-41% (v/v) acetonitrile (ACN) fraction than for the other two venoms.