Send to

Choose Destination
Free Radic Biol Med. 2008 Jul 1;45(1):18-31. doi: 10.1016/j.freeradbiomed.2008.03.020. Epub 2008 Apr 4.

The chemical biology of nitric oxide: implications in cellular signaling.

Author information

Department of Medicinal Chemistry and Pharmacognosy, School of Pharmacy, University of Illinois at Chicago, Chicago, IL 60612, USA.


Nitric oxide (NO) has earned the reputation of being a signaling mediator with many diverse and often opposing biological activities. The diversity in response to this simple diatomic molecule comes from the enormous variety of chemical reactions and biological properties associated with it. In the past few years, the importance of steady-state NO concentrations has emerged as a key determinant of its biological function. Precise cellular responses are differentially regulated by specific NO concentration. We propose five basic distinct concentration levels of NO activity: cGMP-mediated processes ([NO]<1-30 nM), Akt phosphorylation ([NO] = 30-100 nM), stabilization of HIF-1alpha ([NO] = 100-300 nM), phosphorylation of p53 ([NO]>400 nM), and nitrosative stress (1 microM). In general, lower NO concentrations promote cell survival and proliferation, whereas higher levels favor cell cycle arrest, apoptosis, and senescence. Free radical interactions will also influence NO signaling. One of the consequences of reactive oxygen species generation is to reduce NO concentrations. This antagonizes the signaling of nitric oxide and in some cases results in converting a cell-cycle arrest profile to a cell survival profile. The resulting reactive nitrogen species that are generated from these reactions can also have biological effects and increase oxidative and nitrosative stress responses. A number of factors determine the formation of NO and its concentration, such as diffusion, consumption, and substrate availability, which are referred to as kinetic determinants for molecular target interactions. These are the chemical and biochemical parameters that shape cellular responses to NO. Herein we discuss signal transduction and the chemical biology of NO in terms of the direct and indirect reactions.

[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Elsevier Science Icon for PubMed Central
Loading ...
Support Center