Soluble and particle-bound trehalase in extracts from larvae, pupae, and adults of Musca domestica

Trehalase activity was measured in tissue homogenates and extracts from the larval, pupal, and adult stages of Musca domestica, the common housefly. The tissue homogenates were separated into soluble and particlebound fractions by differential centrifugation, and the trehalase activities of the fractions were measured. The trehalase specific activity (units of enzyme/mg protein) in homogenates from adult insects was nearly twenty times greater than activity in homogenates of larvae. Homogenates of pupae showed intermediate values. In both the adults and larvae the enzyme activity was approximately evenly distributed between soluble and particle-bound forms, whereas 95 per cent of the trehalase activity in the extract of pupae was in the soluble fraction. The results show that the form and amount of trehalase present during housefly development is adjusted to accommodate the enzyme's physiological rôle of splitting trehalose to glucose for the insect's use as an energy source.