Calmodulin activity in whole body and fat body tissue extracts of Heliothis virescens larvae

Calmodulin is an activator of many enzymatic activities. Total calmodulin activity in tissue extracts of Heliothis virescens larvae (5th instar), assayed by cyclic phosphodiesterase activation, was 0.48 unit/gm for whole body and 22.2 units/gm for fat body. Specific calmodulin activity was 0.1 unit/mg protein for whole body and 3.0 units/mg protein for fat body. The larval fat body is therefore the main site of calmodulin activity in this lepidopterous larva.