Partial characterization of phenoloxidase enzyme in the hemocytes of Helicoverpa armigera Hübner (Lepidoptera: Noctuidae)

AbstractPhenoloxidase (PO) activity plays a key role in the innate immune responses of insects, which catalyzes the biosynthesis of quinones and other reactive intermediates to eliminate invading pathogens and parasites. This study was conducted to characterize the biochemical properties of the PO enzyme from the hemocytes of the cotton bollworm Helicoverpa armigera Hübner. The maximum activity of PO occurred at pH 6 and at 30°C and it was stable for 12–24h. The Michaelis–Menten constant (Km) and the maximal velocity (Vmax) were determined as 1.86mM and 0.35U/mg protein, respectively. This is the first report of PO characterization in H. armigera from Iran that provided biochemical optimized conditions for its activity, and with these ongoing studies, our aim will be to develop new strategies for cotton bollworm control using disruptors of the immune system