Thermoactivity and effects of organic solvents on digestive lipase from hepatopancreas of the green crab

Unlike classical digestive lipases, the crab digestive lipase (CDL) displayed its maximal activity at a high temperature. The CDL activity's optimal temperature, when using emulsified or monomolecular film as Substrate, was 60 degrees C. To our knowledge, this is the first report of an animal digestive lipase having such an optimal temperature. The maximum activity of CDL appeared at pH 8. Lipase activity was compatible with the presence of organic solvents, except for butanol. Furthermore, the hydrolysis was found to be specifically dependent on the presence of Ca2+ ions, since no significant CDL activity was detected in the presence of ion chelators such as EDTA. Nevertheless, the CDL does not require Ca2+ to trigger the hydrolysis of tributyrin emulsion. Interestingly, Zn2+ and Cu2+ ions acted as strong inhibitors of CDL activity when using tributyrin as substrate. Lipase stability in the presence of organic solvents, as well as at high temperatures, makes it a good candidate for application in non-aqueous catalysis. (C) 2009 Elsevier Ltd. All rights reserved.