Figure 4

Biochemical properties of SPLA2 compared with these of OPLA2 and DrPLA2. (A) Effect of Ca²⁺ concentration on SPLA2, OPLA2 and DrPLA2 activity. Enzyme activity was measured at various concentrations of Ca²⁺ using PC as substrate at pH 8.5 and at 40°C in the presence of 4 mM NaTDC. The star symbol indicates the absence of phospholipase activity checked in the absence of CaCl₂ and in the presence of 10 mM EDTA. (B) Effect of increasing concentration of NaTDC on SPLA2_, OPLA2 and DrPLA2 activities. (C) Effect of increasing concentration of NaDC on SPLA2_, OPLA2 and DrPLA2 activities. PLA2 activity was measured using PC emulsion as substrate at under standard conditions. (D) Long-term stability of SPLA2 stored in the refrigerator (5 °C) and at room temperature (25 °C). Assays were carried out under standard conditions as described in the text. SPLA2 (black circle); DrPLA2 (black square); OPLA2 (open square). All experiments were repeated at least three times