Use of a Metallopeptide-Based Mimic Provides Evidence for a Proton-Coupled Electron-Transfer Mechanism for Superoxide Reduction By Nickel-Containing Superoxide Dismutase

Use of a Metallopeptide-Based Mimic Provides Evidence for a Proton-Coupled Electron-Transfer Mechanism for Superoxide Reduction By Nickel-Containing Superoxide Dismutase:

Sneaky little SOD! A metallopeptide-based mimic of nickel-containing superoxide dismutase was used to probe the mechanism of superoxide reduction by the metalloenzyme. Kinetic studies suggest a proton-coupled electron-transfer mechanism; large H/D kinetic isotope effects (KIE) are observed. XAS studies suggest the transferred H-atom is in the form of a Ni^II-S(H)-Cys moiety (see graph).