Abstract 1177 Solving the mystery of L-DOPA 2,3-dioxygenase inactivation: evidence for superoxide

Dioxygenase enzymes are essential protein catalysts for breaking down catecholic rings. L-DOPA 2,3-Dioxygenase enzymes use an active site FeII to activate oxygen, generating superoxide, which then cleaves the aromatic ring of L-DOPA or alternative catecholic substrates. We hypothesized that L-DOPA 2,3-dioxygenase enzymes engage in self-inactivation by releasing superoxide mid-reaction, preventing the oxidation of the substrate, and resulting in the inactivation of the enzyme. The inactivation of L-DOPA 2,3-dioxygenase and its mutants L46R and L46W was detected by oxygen electrode using an “uncoupling experiment” to measure oxygen consumption with and without superoxide dismutase (SOD) and catalase.