Ester synthesis catalyzed by polyethylene glycol-modified lipase in benzene.

Lipoprotein lipase, which catalyzes hydrolysis of emulsified triglycerides or water-insoluble esters, was modified with 2,4-bis(o-methoxy-polyethylene glycol)-6-chloro-s-triazine(activated PEG2). The modified lipase, in which 55% of the total amino groups in the lipase molecule, was soluble in organic solvents such as benzene, toluene, chloroform and dioxane. The modified lipase could catalyze ester synthesis reaction in benzene. When very hydrophobic substrates of lauryl alcohol and stearic acid were used, the ester synthesis reaction proceeded efficiently in the transparent benzene solution with the maximum activity of approximate 5.0 mumoles/min/mg of protein. Ester exchange and aminolysis reactions were also conducted with the modified lipase in benzene.