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ATPases, an important target of insecticides, are enzymes that hydrolyze ATP and use the energy released in that process to accomplish some type of cellular work. Pachymerus nucleorum (Fabricius) larvae possess an ATPase, that presents high Ca-ATPase activity, but no Mg-ATPase activity. In the present study, the effect of zinc and copper ions in the activity Ca-ATPase of that enzyme was tested. More than 90% of the Ca-ATPase activity was inhibited in 0.5 mM of copper ions or 0.25 mM of zinc ions. In the presence of EDTA, but not in the absence, the inhibition by zinc was reverted with the increase of calcium concentration. The inhibition by copper ions was not reverted in the presence or absence of EDTA. The Ca-ATPase was not inhibited by treatment of the ATPase fraction with copper, suggesting that the copper ion does not bind directly to the enzyme. The results suggest that zinc and copper ions form a complex with ATP and bind to the enzyme inhibiting its Ca-ATPase activity.

Hexokinase enzyme was studied by means of starch-agarose gel electrophoresis in Plebeia droryana. Three anodal bands with enzyme activity were observed during the development: hexokinase-1 (HK-1), the intensity of which increases from larvae to adult, probably related with energy supply to thoracic flight muscles and, therefore, with flight activity; hexokinase-2 (HK-2), that reaches maximum intensity in clear brown eyed pupae and hexokinase-3 (HK-3), the intensity of which reaches maximum peak in winged pupae and is not observed in the adult phase. This isozyme should have important functions in the bee metamorphosis.