Propionate 3-nitronate (P3N) is a natural toxin that irreversibly inhibits the Krebs cycle – a life sustaining metabolic pathway. Nitronate monooxygenase detoxifies P3N using molecular oxygen. Among ∼500 NMO sequences from various organisms, NMO has evolved to contain Y109, Y254, Y299, Y303, K307, and H183 in putative NMOs. In this thesis, the role of these select residues in the binding and oxidation of P3N is studied. Using steady state kinetics and UV-visible absorption spectroscopy, Y109, Y254, Y299, Y303, and K307 were found to have no role in the turnover of P3N. Utilizing steady-state, rapid kinetics, and x-ray crystallography, H183 was determined to be an essential residue in binding P3N into an enzyme-substrate complex competent for the single electron transfer between P3N and the reactive center of the enzyme.