Which term best describes the class of molecules that includes nitric oxide and peroxynitrite in this context?

Which term best describes the class of molecules that includes nitric oxide and peroxynitrite in this context?

• A. Reactive nitrogen species (RNS)
• B. Reactive oxygen species (ROS)
• C. Lipid mediators
• D. Cytokines

Answer: (A)

Nitric oxide and its reactive nitrogen–containing products are best described as Reactive Nitrogen Species. Nitric oxide is a small, diffusible radical produced by immune cells for signaling and antimicrobial effects. When it encounters superoxide, NO quickly forms peroxynitrite, a potent oxidant that can nitrate proteins, lipids, and DNA. This combination of nitrogen-centered reactivity makes NO and peroxynitrite fit squarely into the reactive nitrogen species category. Reactive oxygen species, by contrast, are oxygen-based and include species like superoxide and hydrogen peroxide. Lipid mediators and cytokines are different families—lipid mediators are signaling lipids derived from arachidonic acid, and cytokines are protein signaling molecules—so they don’t group NO and peroxynitrite together.

Nitric oxide and its reactive nitrogen–containing products are best described as Reactive Nitrogen Species. Nitric oxide is a small, diffusible radical produced by immune cells for signaling and antimicrobial effects. When it encounters superoxide, NO quickly forms peroxynitrite, a potent oxidant that can nitrate proteins, lipids, and DNA. This combination of nitrogen-centered reactivity makes NO and peroxynitrite fit squarely into the reactive nitrogen species category. Reactive oxygen species, by contrast, are oxygen-based and include species like superoxide and hydrogen peroxide. Lipid mediators and cytokines are different families—lipid mediators are signaling lipids derived from arachidonic acid, and cytokines are protein signaling molecules—so they don’t group NO and peroxynitrite together.