1. 1. Measurements of maximal enzyme activities were combined with an electrophoretic study of isozyme make-up in an examination of triglyceride, diglyceride and monoglyceride lipases from the flight muscle, fat body and gut of the cockroach, Periplaneta americana and the locust, Locusta migratoria and from the flight muscle and fat body of the moth, Polia adjuncta. 2. 2. Tri-, di- and mono-glyceride lipases were present in all tissues of the insects with diglyceride lipase ≥ triglyceride lipase activity in all cases and monoglyceride lipase ≥ diglyceride lipase activity in locust and moth. 3. 3. In the flight muscle, a strong correlation was found between the activities of lipases and the known use of lipid as a fuel for flight in these insects. Lipase activities were lowest in the cockroach (a carbohydrate-based flight metabolism), intermediate in the locust (both carbohydrate and lipid-fueled flight), and highest in the moth (a non-feeding, lipid-catabolizing adult) flight muscle. 4. 4. Polyacrylamide gel electrophoresis, using substrate-impregnated gels and stained for fatty acids released by lipase action, demonstrated the presence of tissue specific isozymes of tri-, di- and mono-glyceride lipases in the three insects. In addition, some, but not all, tissues showed multiple molecular forms of one or more of the lipases. 5. 5. Diglyceride and monoglyceride lipase activities in both flight muscle and fat body of the insects coelectrophoresed suggesting the possibility that these two lipase activities might be catalyzed by a single enzyme protein.

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Insect Biochemistry
Department of Biology

Male, K.B. (Keith B.), & Storey, K. (1981). Enzyme activities and isozyme composition of triglyceride, diglyceride and monoglyceride lipases in Periplaneta americana, Locusta migratoria and Polia adjuncta. Insect Biochemistry, 11(4), 423–427. doi:10.1016/0020-1790(81)90076-7