End product specificity of triacylglycerol lipases from intestine, fat body, muscle and haemolymph of the American cockroach,Periplaneta americana L.

The triacylglycerol-hydrolyzing capacity of tissue homogenates has been investigate for midgut, fat body, thoracic musculature and haemolymph of the American cockroach, Periplaneta americana. The greatest lipolytic activity was demonstrated in midgut homogenates with decreasing levels of activity present in fat body, muscle and haemolymph. Comparison of the lipolytic products resulting from triacylglycerol hydrolysis indicates that midgut homogenates effect the production of sn-2-monoacylglycerols and free fatty acids, whereas the other tissues that were examined favor the accumulation of diacylglycerols. Stereospecific analysis of the diacylglycerol products of triacylglycerol hydrolysis demonstrated that the lipolytic activities of midgut and muscle homogenates result in the production of a racemic mixture of the sn-1,2- and sn-2,3-enantiomers, but the fat body and haemolymph show a preference for the accumulation of the sn-1,2-isomer.