Distinctive Distribution of Secretory Phospholipases A(2) in the Venoms of Afro-Asian Cobras (Subgenus: Naja, Afronaja, Boulengerina and Uraeus)

The protein abundances of phospholipases A(2) in cobra venom proteomes appear to vary among cobra species. To determine the unique distribution of snake venom phospholipases A(2) (svPLA(2)) in the cobras, the svPLA(2) activities for 15 cobra species were examined with an acidimetric and a colorimetric assay, using egg yolk suspension and 4-nitro-3-octanoyloxy benzoic acid (NOBA) as the substrate. The colorimetric assay showed significant correlation between svPLA(2) enzymatic activities with the svPLA(2) protein abundances in venoms. High svPLA(2) activities were observed in the venoms of Asiatic spitting cobras (Naja sputatrix, Naja sumatrana) and moderate activities in Asiatic non-spitters (Naja naja, Naja atra, Naja kaouthia), African spitters (subgenus Afronaja), and forest cobra (subgenus Boulengerina). African non-spitting cobras of subgenus Uraeus (Naja haje, Naja annulifera, Naja nivea, Naja senegalensis) showed exceptionally low svPLA(2) enzymatic activities. The negligible PLA(2) activity in Uraeus cobra venoms implies that PLA(2) may not be ubiquitous in all snake venoms. The svPLA(2) in cobra envenoming varies depending on the cobra species. This may potentially influence the efficacy of cobra antivenom in specific use for venom neutralization.