A Thermoactive Secreted Phospholipase A₂ Purified from the Venom Glands of Scorpio Maurus: Relation Between the Kinetic Properties and the Hemolytic Activity

A lipolytic activity was located in the scorpion venom glands (telsons), from which a phospholipase A₂ (Sm-PLVG) was purified. Like known phospholipases A₂ from scorpion venom, which are 14-18 kDa proteins, the purified Scorpio maurus-Phospholipase from Venom Glands (Sm-PLVG) has a molecular mass of 17 kDa containing long and short chains linked by disulfide bridge. It has a specific activity of 5500 U/mg measured at 47 °C and pH 8.5 using phosphatidylcholine as a substrate in presence of 8 mM NaTDC and 12 mM CaCl₂. The NH₂-terminal amino acid sequences of the purified Sm-PLVG showed similarities with those of long and short chains of some previously purified phospholipases from venom scorpions. Moreover, the Sm-PLVG exhibits hemolytic activity toward human, rabbit or rat erythrocytes. This hemolytic activity was related to its ability to interact with phospholipids' monolayer at high surface pressure. These properties are similar to those of phospholipases isolated from snake venoms.