The reactions of hemeproteins with oxygen and carbon monoxide will be studied in terms of the ways in which O2 and CO can bind as a ligand to the iron atom within the protein and, once bound, how the ligand may undergo reactions. Hemeproteins to be examined include the hemoglobins of the red cell that transport O2 and CO, the myoglobins of heart muscle that store O2, and heart cytochrome c oxidase, the major O2 utilizing and energy producing site in the cell. The reactions to be evaluated include those that involve conversion of O2 to superoxide, peroxide, and hydroxyl radical (compounds that can be destructive to normal cellular constituents) as a result of abnormalities in hemoglobin protein structure or due to the presence of "oxidant drugs", certain pollutants, and other agents. Reactions of respiratory inhibitors, e.g., cyanide, azide, and CO with cytochrome c oxidase will also be explored, especially the recent finding that oxidase can catalyze oxidation (detoxification) of CO through reaction with O2 to give CO2. Approaches to be employed include infrared, nuclear magnetic resonance, and ultraviolet-visible spectroscopic probes.