Abstract
We are investigating the redox chemistry of the heme domains of wild type BM3 (WT) and mutant 1-12G. Compared to WT, 1-12G combines 16 amino acid mutations to produce BM3 variants that show high activity towards a variety of substrate. We hypothesize that these differences in catalysis are partially due to differences in the redox properties of the heme. Evidence suggests that the 16 mutations in 1-12G cause some perturbation of the heme?s electronics, leading to alterations in redox properties. One aspect of this project is to monitor and investigate the P450 catalytic production of hydrogen peroxide (H2O2) via an oxygen reaction. To investigate this oxygen reaction, surfactant films were cast onto the surface of glassy carbon rotated disk electrodes (GCE). Experiments using rotated electrodes allow one to apply the Levich equation. Using this equation and the values of the variables for oxygen in water, theoretical plots for the one, two, and four electron reduction of oxygen can be generated. The second aspect of this project is concerned with binding molecular wires to WT. When different wires are bound to the metal center they lead to different degrees of heme hydration. These different hydration states will undoubtedly lead to different heme potentials, which can be measured by film voltammetry. We confined the enzyme and have attempted to confine WT with the wire bound in a surfactant film (DDAB) that facilitates electron transfer. The surfactant molecules self assemble into a highly ordered phase allowing us to measure the potentials.
