Protein variation in the venom spat by the red spitting cobra, Naja pallida (Reptilia: Serpentes)

摘要

The venom spat by red spitting cobras (Naja pallida) was analyzed to document variations in protein composition occurring over short temporal periods (less that 5 min). These cobras exhibited distinct control of venom flow with spits averaging 1.7% of the volume of the venom gland, thus enabling the cobras to rapidly expel over 40 consecutive spits. Variations in the low and high molecular weight proteins were observed when comparing the lst, 20th and 40th spits produced by the same specimens. The first few spits were characterized by a distinctive 9 kDa protein which was never observed beyond the 7th spit, was present in milked venom and was present when the spitting behavior was preceded by a 5 min period of induced defensive behaviors.