Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Atmos. Chem. Phys., 17, 11819-11833, 2017
https://doi.org/10.5194/acp-17-11819-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
06 Oct 2017
Light-induced protein nitration and degradation with HONO emission
Hannah Meusel1, Yasin Elshorbany2,8, Uwe Kuhn1, Thorsten Bartels-Rausch3, Kathrin Reinmuth-Selzle1, Christopher J. Kampf4, Guo Li1, Xiaoxiang Wang1, Jos Lelieveld5, Ulrich Pöschl1, Thorsten Hoffmann6, Hang Su7,1, Markus Ammann3, and Yafang Cheng1,7 1Max Planck Institute for Chemistry, Multiphase Chemistry Department, Mainz, Germany
2NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
3Paul Scherrer Institute, Villigen, Switzerland
4Johannes Gutenberg University of Mainz, Institute for Organic Chemistry, Mainz, Germany
5Max Planck Institute for Chemistry, Atmospheric Chemistry Department, Mainz, Germany
6Johannes Gutenberg University of Mainz, Institute for Inorganic and Analytical Chemistry, Mainz, Germany
7Institute for Environmental and Climate Research, Jinan University, Guangzhou, China
8Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland, USA
Abstract. Proteins can be nitrated by air pollutants (NO2), enhancing their allergenic potential. This work provides insight into protein nitration and subsequent decomposition in the presence of solar radiation. We also investigated light-induced formation of nitrous acid (HONO) from protein surfaces that were nitrated either online with instantaneous gas-phase exposure to NO2 or offline by an efficient nitration agent (tetranitromethane, TNM). Bovine serum albumin (BSA) and ovalbumin (OVA) were used as model substances for proteins. Nitration degrees of about 1 % were derived applying NO2 concentrations of 100 ppb under VIS∕UV illuminated conditions, while simultaneous decomposition of (nitrated) proteins was also found during long-term (20 h) irradiation exposure. Measurements of gas exchange on TNM-nitrated proteins revealed that HONO can be formed and released even without contribution of instantaneous heterogeneous NO2 conversion. NO2 exposure was found to increase HONO emissions substantially. In particular, a strong dependence of HONO emissions on light intensity, relative humidity, NO2 concentrations and the applied coating thickness was found. The 20 h long-term studies revealed sustained HONO formation, even when concentrations of the intact (nitrated) proteins were too low to be detected after the gas exchange measurements. A reaction mechanism for the NO2 conversion based on the Langmuir–Hinshelwood kinetics is proposed.

Citation: Meusel, H., Elshorbany, Y., Kuhn, U., Bartels-Rausch, T., Reinmuth-Selzle, K., Kampf, C. J., Li, G., Wang, X., Lelieveld, J., Pöschl, U., Hoffmann, T., Su, H., Ammann, M., and Cheng, Y.: Light-induced protein nitration and degradation with HONO emission, Atmos. Chem. Phys., 17, 11819-11833, https://doi.org/10.5194/acp-17-11819-2017, 2017.
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In this study we investigated protein nitration and decomposition by light in the presence of NO2 via flow tube measurements. Nitrated proteins have an enhanced allergenic potential but so far nitration was only studied in dark conditions. Under irradiated conditions we found that proteins predominantly decompose while forming nitrous acid (HONO) an important precursor of the OH radical. Unlike other studies on heterogeneous NO2 conversion we found a stable HONO formation over a long period.
In this study we investigated protein nitration and decomposition by light in the presence of...
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