Nitric oxide (NO) is inactivated in the human body when exposed to superoxide (02-). This reaction forms peroxynitrite (ONOO). Superoxide is produced in the cardiac system by several mechanisms, including NAD(P)H oxidase. Superoxide dismutase (SOD) breaks down superoxide into oxygen and hydrogen peroxide. This prevents superoxide from reacting with nitric oxide and allows normal function to take place. Superoxide and peroxynitrite are main contributors to vascular disease in the human body, in particular hypertension.
Strobel, A. (2008). Computational Modeling of Oxidative Stress: an Analysis of NAD(P)H Effects on Nitric Oxide and Superoxide During Hypertension. Inquiry: The University of Arkansas Undergraduate Research Journal, 9(1). Retrieved from https://scholarworks.uark.edu/inquiry/vol9/iss1/17