Activity of Dehydrogenase Enzymes during the Metamorphosis of the Mealworm, Tenebrio Molitor Linnaeus1

Abstract

No evidence was found for formic, beta-hydroxybutyric, choline, or glutamic dehydrogenases in the larva; glutamic1 appeared towards the end of the pupal stage. Succinate and alpha-glycerophosphate did not require DPN for their oxidation, but its addition greatly stimulated utilization of the latter substrate. Alcohol, glucose, glutamic, and malic dehydrogenases could not act without DPN; isocitric dehydrogenase and malic enzyme required TPN. Lactic dehydrogenase did not require DPN in the larva; however, in the pupa and adult its addition increased the oxidation of lactate. Curves for the activities of malic and succinic dehydrogenases and the malic enzyme were U-shaped during metamorphosis. Since the activity of succinic dehydrogenase was lower than those of the other two enyzmes, it could be a determining factor in the U-shaped respiratory curve. The high activity of malic enzyme coupled with a low value for lactic dehydrogenase makes the accumulation of lactate unlikely, since the malic enzyme would convert pyruvate to malate under anaerobic conditions.