Measurement of NADPH oxidase activity by monitoring the rates of OCR. (A) Comparison of nondifferentiated and differentiated HL60 cells in their response to PMA stimulation. (B) Effect of mitochondrial inhibitors (1 μM rotenone, ROT, and 1 μM antimycin A, ANT) on basal and PMA-stimulated oxygen consumption by dHL60 cells. (C,D) Effect of diphenyleneiodonium (DPI, 10 μM) on basal (ΔOCRBasal) and PMA-stimulated (ΔOCRPMA) oxygen consumption by dHL60 cells. (This research was originally published in Journal of Biological Chemistry. Zielonka, J., Cheng, G., Zielonka, M., Ganesh, T., Sun, A., Joseph, J., Michalski, R., O’Brien, W. J., Lambeth, J. D., & Kalyanaraman, B. High-throughput assays for superoxide and hydrogen peroxide: design of a screening workflow to identify inhibitors of NADPH oxidases. J. Biol. Chem. 2014; 289:16176–16189, and Zielonka, J., Zielonka, M., VerPlank, L., Cheng, G., Hardy, M., Ouari, O., Ayhan, M. M., Podsiadly, R., Sikora, A., Lambeth, J. D., & Kalyanaraman, B. Mitigation of NADPH Oxidase 2 Activity as a Strategy to Inhibit Peroxynitrite Formation. J. Biol. Chem. 2016; 291:7029–7044. © the American Society for Biochemistry and Molecular Biology) (24, 79)