Effect of MMOB on electron transfer from MMOR3e to oxidized MMOH at 4 °C. (A) Parallel fits (solid lines) through kinetic data recorded at 470 nm for the reaction of 20 μM MMOR with 10 μM MMOH in the presence of no MMOB (red), 5 μM MMOB (blue), 10 μM MMOB (green), 20 μM MMOB (purple), and 40 μM MMOB (orange). (B) Variation of rate constants with MMOB concentration: k1 (circles), k2 (squares), and k3(triangles). (C) Partitioning of electrons through the rapid (k1 and k2, circles) and slow (k3 and k4, squares) reaction phases as a function of MMOB concentration.