SPECIFICITY AND LOCALIZATION OF LIPOLYTIC-ACTIVITY IN ADULT DROSOPHILA-MELANOGASTER

The triacylglycerol lipases present in adult Drosophila melanogaster h ave been investigated. Different lipase activities are present in vari ous tissues in the fly. In particular, an abundant lipase activity is present in the male accessory gland. An esterase null mutant was used to confirm that the enzyme activity was due to a distinct lipase and n ot non-specific activity from esterase 6 which is also abundant in acc essory glands. The properties of the accessory-gland lipase were inves tigated, and pH optima and substrate utilization suggest that it has s ome similarities to vertebrate bile-salt-stimulated lipase. Lipase act ivity is significantly reduced in males and increased in females short ly after mating. This finding suggests that lipase activity is transfe rred to the female and may be important in mating and reproduction in Drosophila.