The hydrolysis of phosphatidylcholine by phospholipase A(2) in microemulsion as microreactor

Phospholipase A(2) (PLA(2)) was used to hydrolyze phosphatidylcholine (PC) in microemulsions. Phase diagrams were constructed for mixtures of alcohols (C-2-C-6), medium chain triglycerides (tricaprylin, TC) or vegetable oils, PC and water, and areas corresponding to isotropic systems were identified . The PC hydrolysis was carried out with high yields at various PC/(TC+alco hol) compositions within the areas of isotropic systems at increasing amoun ts of solubilized water. The initial reaction rates depended on the aggregation state of the PC (siz e and nature of microemulsion structures), as well as on temperature and mo de of calcium addition. At low enzyme concentrations, hydrolysis was preceded by a "lag phase" foll owed by an abrupt increase in rate. By contrast, no latency was observed at higher PLA(2) PC ratios and the rate was significantly higher. The easy access of the enzyme to the substrate in the curved phospholipid-c ontaining microemulsion particles facilitate activation of the enzyme and " pushes" the reaction to completion. Hence, these microemulsions can serve a s microreactors for the enzymatic high yield hydrolysis.