Acid and alkaline phosphomonoesterases in Egyptian snake venoms

Non-specific acid and alkaline phosphomonoesterases could be demonstrated in two viperids (Cerastes cerastes and Cerastes vipers) and two elapids (Naja haje and Naja nigricollis). The latter could be a natural source for the production of these enzymes. The activities of both enzymes in elapids were greater than in viperids. N. nigricollis was the only to show acid phosphatase activity exceeding its alkaline one. The optimum pH values recorded for acid phosphatase was 4.0 and 4.9 and for alkaline phosphatase 9.0 and 10.0 in viperids and elapids, respectively. Optimum substrate concentration for both enzymes in viperids was 0.01 M, while for acid phosphatase in N. haje and N. nigricollis it was 0.125 and 0.150 M; and for their alkaline phosphatases the values were 0.150 and 0.125 M, respectively. Mg++ behaved as an activator for both enzymes in all venoms investigated, while Zn++ showed either no or slight activating effect. Fluoride ions as well as EDTA showed certain inhibitory action. Both enzymes in the crude venoms were heat-labile.