Purification and Partial Characterization of a Thrombin-Like Enzyme (AH144) from Venom of Iranian Snake Agkistrodon Halys

The snake venom´s thrombin-like enzymes comprise a number of serine proteases, which are functionally and structurally related to thrombin. Purification and partial characterization of a thrombin-like enzyme from the venom of the Iranian snake, Agkistrodon halys, was the aim of this study. Purification was carried out by a combination of variety of chromatographic methods that included: gel filtration on Sephadex G-50, ion-exchange chromatography on DEAE-Sepharose and HPLC with a C18 column. A trial for the purification of protease resulted in an enzyme with specific activity of 721.2 (μmol/min/mg), which was purified by 72.1 fold. The purified thrombin-like enzyme designated AH144 was found to have a molecular weight of approximately 30.5 kDa. This thrombin-like enzyme had the highest activity at 37 °C and pH 7.5. Enzyme activity increased as its concentration increased, and the purified enzyme did not have any effect on casein. AH144 demonstrated clotting and proteolytic activities in the presence of the human plasma and the synthetic substrate (BApNA), respectively. Data emphasized the possibility of AH144 for quantitative determination of fibrinogen.