Purification of hemorrhagic SVMPs from venoms of three vipers of Egypt.

Three viper P-III hemorrhagic SVMPs: EpyHTI (60 kDa), EcoHTI (60 kDa) and CcHTI (58 kDa) of the most dangerous vipers Echis pyramidum, Echis coloratus and Cerastes cerastes, respectively were purified and characterized in a set of biochemical assays. The SVMPs were purified by applying a protocol of three successive chromatographic steps. The enzymatic activity of the purified SVMPs was stimulated by the divalent cations Ca2+, Mg2+ and inhibited by metalloproteinase inhibitors and (Zn2+, Mn2+, Ni2+, Co2+, Cu2+ and Hg2), whereas inhibitors of serine and cysteine proteinases had no effect. The digestion of the BM proteins by purified SVMPs was much different, indicating different cleavage specificity for each of the purified SVMPs. Based on their intense hemorrhagic activity and molecular masses, the purified enzymes were hypothesized to belong to the P-III class of SVMPs. The three SVMPs possess close biochemical properties, but are different with respect to cleavage site, (fibronectin and fibrinogen). Furthermore, the described purification procedure allows simple preparation of appreciable quantities of the three SVMPs for further studies.