Inhibition of lipases by phosphonates

Ethyl hexylchlorophosphonate and analogues thereof were investigated as inhibitors of lipases. Both microbial and mammalian lipases were irreversibly inhibited. The inhibition could be monitored by p-nitrophenol release from the corresponding ethyl p-nitrophenyl hexylphosphonate inhibitor. Quantitative analysis of the data indicated that a 1:1 lipase-inhibitor complex was formed during inhibition. Enantioselective inhibition was found for the lipases derived from Candida antarctica and Rhizomucor miehei using pure enantiomers of ethyl p-nitrophenyl hexylphosphonate as inhibitors. Using the same inhibitor, reversed enantioselectivity was found for the protease alpha-chymotrypsin as compared to the two lipases.