Although the presence of ozone and NOx gases (i.e. NO. and NO2.) are often linked to an increase in respiratory conditions such as asthma, the mechanism by which these pollutants cause respiratory distress is still not clear. Interestingly, the highly reactive NO3. (formed in the atmosphere at night by reaction of O3 and NO2.) has been somewhat overlooked as a possible respiratory irritant despite numerous studies on its role in the atmosphere.
In this HOT paper Uta Wille and colleagues at the University of Melbourne follow up a previous study published in Chem. Comm. which identified the products of the reaction of the NO3 radical with amino acids. Now, they have simulated the exposure of proteins present at the surface of the respiratory tract to a number of environmental pollutants, determining clear reaction pathways resulting in aromatic ring nitration of the amino acids studied. They note that nitrated aromatic amino acids are often observed in a wide range of inflammatory-immune responses such as asthma and cystic fibrosis, leading them to suggest that the NO3 radical could actually be the real culprit in certain pollution-related diseases.
You can read the full details of this interesting study online here (it’s free to access for the next month!).
This paper is included in the OBC special we themed issue on radical chemistry that will be published soon. Keep an eye on it!
Damage of aromatic amino acids by the atmospheric free radical oxidant NO3˙ in the presence of NO2˙, N2O4, O3 and O2
Catrin Goeschen, Natalia Wibowo, Jonathan M. White and Uta Wille
Org. Biomol. Chem., 2011, Advance Article
And the previous Chem. Comm. paper can be found here:
Can the night-time atmospheric oxidant NO3˙damage aromatic amino acids?
Duanne C. E. Sigmund and Uta Wille
Chem. Commun., 2008, 2121-2123