In this study, the electrophoretic pattern of venom of Echis was studied and compared in the populations of southeast Sistan and Baluchistan (Zabol), southern Khorasan (Cain) and Khuzestan (Aghajari), southwest of Iran. For this purpose, toxicity (mean lethal dose, LD50, and SDS-PAGE and HPLC) methods was used to evaluate venom protein composition. The results show that the color of lyophilized crud venoms of these three snakes populations are, yellowish cream, and no differences in color was seen. The toxicity level (LD50) of Zabol venom was 28.4 ± 4.5 μg / mouse, which showed no significant difference with the toxicity of Ghaen venom, 24.4 ± 4.15μg / mouse, but the mean toxicity of Aghajari venom was 6.7 ± 0.07, 6 μg / mouse which showed a significant difference in comparison with the two previous venoms at P ≤ 0.05. The pattern of electrophoresis of venoms from three populations of Zabol, Ghaen and Aghajari show that protein compositions in the molecular weight range of were 21.5, 21.9, 39.5, 82.5, 92.88 KDa. Although the protein densities were different in three venoms, some proteins band either were not obvious or with a lesser densities in electrograms. However, the ratio of some of the protein bands was different, indicating differences in the composition of the three venoms from Echis of three different regions. In the HPLC profile, chromatography peaks clearly indicate that there are significant differences in protein composition and about 14 distinct peaks were observed. Significant differences were observed in the relative intensity of the peaks and the ratio of the peaks to the total area at a given retention time. The results of this study indicate the difference in venom protein composition of Echis snake populations from three different regions of Iran. These observations reveal that venoms extracted from different populations of Echis is even different in closely related populations (Our previous study). Thus studying the protein composition of venom can be an effective complementary tool to identify and may classify the different species of a specie, and antivenin producers should pay particular attention to these differences in the composition of venom in medically important species. These results suggest, that there is a variation inEchis snakes from different geography and climates of Iran, and these factors affect the composition of proteins and the toxicity of venom. Therefore, it is recommended that manufacturers of antivenins would use venoms from Echis of different regions of the country.
