Expression and characterization of a novel plaminogen activator from green pit viper (Cryptelytrops albrolabris)

Abstract

Snake venome is a mixture of several proteins affecting hematostatic system. Serine protease is one of the important protein families found in Green pit viper (GPV, Cryptelytrops allbolabris) venom. In this study, a novel serine protease gene was cloned from the GPV venom gland cDNA library. Amino acid sequence analysis predicted that it was a plasminogen activator. The serine protease cDNA was cloned in the pPICZαA vector and, then, expressed in the Pichia pastoris system. The histidine-tagged recombinant protein production was higher after the induction using 1.0% (v/v), compared with 0.5%, of methanol. This system was able to produce the 37 kDa protein on a Western blot probed by anti polyhistidine antibody. In vitro activities of the protein was tested and found that it contained a plasminogen activator activity. However, there was no effect on platelet aggregarion. This protein has a potential to be a therapeutic thrombolytic agent in the future.