Chemical Inactivation of Lipase in Organic Solvent: A Lipase from Pseudomonas aeruginosa TE3285 is More Like a Typical Serine Enzyme in an Organic Solvent than in Aqueous Media.

A microbial lipase from Pseudomonas aeruginosa TE3285 was treated in anhydrous diisopropyl ether with three kinds of serine-reactive reagents, ethyl p-nitrophenyl methylphosphonate (ENMP), diisopropyl fluorophosphate (DFP), and phenylmethylsulfonyl fluoride (PMSF) to lose its catalytic activity for both transesterification in an organic solvent and ester hydrolysis in aqueous system. In contrast with the facile inactivation in an organic solvent, no or very slow inactivation was observed in an aqueous solution. The lipase was shown to behave more like a typical serine enzyme in an organic solvent than in aqueous solution with regard to the chemical inactivation by serine-reactive reagents. The unique behavior of the lipase in an organic solvent may be associated with inferfacial activation of the lipase, which is one of the most distinct characteristics of the lipase family, and the activiation of lipase could be induced by a hydrophobic interaction with an organic solvent.