Abstract View
Chemical Modification of Protein Exposed to Urban Air
RACHEL L. DAVEY, Erick Mattson, J. Alex Huffman, University of Denver
Abstract Number: 353
Working Group: Aerosol Chemistry
Abstract
Ozone (O3) and nitrogen dioxide (NO2) have been shown to react with pollen proteins to induce chemical modifications like the formation of nitrotyrosine (NTyr). Proteins with these modifications have been shown to induce an immune response in animal models and could promote adverse human health effects including respiratory, cardiopulmonary, or ocular diseases. It has been hypothesized that proteinaceous material suspended in the atmosphere as particulate matter, e.g. on the surface of airborne bioparticles like pollen or spores, could undergo heterogenous reactions to produce chemically modified proteins. Nitrated proteins in and on bioparticles could thus have a negative impact on human health, especially in urban areas. As a way to investigate the protein modification process under ambient reaction conditions, bovine serum albumin (BSA) and ragweed pollen protein (Amb) samples were loaded onto filters and exposed to urban air in Denver, Colorado. Ambient air was drawn through protein-loaded filters for 1-21 days each. The nitration degree was measured via high-performance liquid chromatography (HPLC) using existing literature methods. Losses and measurement artifacts were characterized to support the experimental procedure. O3 loss was quantified from across three commonly used particulate matter (PM) filters (Kynar, HEPA, PP). The PM filters reduced O3 concentrations by 5-80%, with Kynar filters performing with the lowest O3 reduction. Protein mass extraction efficiency as a function of substrate filter material and protein loading mass using both native and nitrated protein is also shown. Finally, preliminary results correlating NTyr formation in BSA and Amb exposed to various concentrations of O3 and NO2 in urban air are shown.