Lipases catalyse hydrolysis of fatty acid anhydrides

Regio-specific and non-regio-specific lipases from mammals and microorganisms catalyse the hydrolysis of short, medium and long-chain fatty acid anhydrides. All the lipases tested in the present study can catalyse the hydrolysis of pure fatty acid anhydrides more efficiently than that of glycerol tributyrate. Molecular turnovers more than four times higher than that measured using glycerol tributyrate were calculated. The presence of 0.5% (by mass) anhydride in a triacylglyceride can double the initial rate of proton release during enzymatic hydrolysis. This should be taken into account when testing the chain specificity of a lipase for various synthetic substrates. Lipase inhibition was found to be associated very often with anhydride hydrolysis. The inhibition rates depended on the anhydride and the origin of the lipase. Inhibition of lipase activity is probably due to the formation of a poorly reversible acyl-lipase complex which differs from the classical fully reversible acyl-lipase complex at the catalytic centre.