Myeloperoxidase (MPO) is the primary enzyme responsible for the production of strong oxidants by neutrophils in response to pathogens. One of the major oxidants produced is hypochlorous acid (HOCl), which can react with amine groups to form the secondary oxidants N-chloramines. These oxidants play a role in the destruction of pathogens, however they also have the potential to damage host cells, and have been implicated in numerous inflammatory diseases. This Thesis explores the potential for selenium containing compounds and enzymes to act as catalytic oxidant scavengers. Reaction rates between MPO-derived oxidants and selenium compounds were determined product characterization of products performed. The reduction of the oxidised products, selenoxides, was examined and the rate constant for the thiol reduction of selenoxides determined. It is demonstrated that selenium and sulfur containing enzymes are capable of scavenging these oxidants, as well as reversing the formation of selenoxides. The ability of selenium compounds to protect against damage induced by treatment of cells with HOCl and N-chloramines was also assessed. Overall, selenium containing compounds and enzymes show potential in scavenging these oxidants with endogenous thiols capable of reversing the oxidised selenium products, making them a potential therapeutic intervention in inflammatory conditions
