NEW APPROACHES IN PROTEIN-CARCINOGEN ADDUCTS

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The general objective of this application is the discovery of new methods for the analysis of chemical carcinogen residues covalently bound to proteins. Such adducts have been demonstrated to be useful in characterizing human exposure to environmental carcinogens. They have also proven valuable in identifying interindividual differences which may play a role in modulating the individual response to a given chemical challenge. The role of these biomarkers in the overall objectives of the Program Project then is to serve as a link between environmental monitoring and health effects. These new methods are expected to provide significant improvements in the accuracy and precision of the quantitative analysis of known adducts as well as in speed and cost of analysis. Improvements in qualitative analysis are also a goal, especially insofar as they will enable the identification of unknown adducts. Four specific aims are designed to accomplish these goals. The first is to develop a general procedure for isolating adducts formed by His(146) of serum albumin. This amino acid resides in a binding site of broad specificity and is expected to react with numerous carcinogens. By identifying adducts formed by this residue it will be possible to elucidate some of the environmental chemicals which are taken up by humans and activated in vivo. A second specific aim is to expand the number of proteins useful for biomonitoring beyond the currently used hemoglobin and serum albumin, with particular emphasis on those which have longer lifetimes so that longer term exposure scenarios can be described. Collagen and the nucleosome core histones have been chosen for investigation. Laser induced fluorescence spectroscopy will be refined as an analytical instrumentation system to complement mass spectrometry for both quantitative analysis and structure elucidation. The final specific aim is to combine a variety of developments and refinements in methodology to produce an accurate and low cost assay for at least one carcinogen, benzo[a]pyrene, suitable for large scale application.