Intramolecular Electron Transfer of [Ni–Fe]-Hydrogenase Monitored by Spectroelectrochemistry with a Porphyrin Indicator

Abstract A method based on spectroelectrochemistry to monitor intramolecular electron transfer in [Ni–Fe]-hydrogenase was developed. The electron transfer generated a color change in manganese–tetra(4-pyridyl)porphyrin (MnTPyP), and time-resolved measurement of the spectral change allowed determination of the intramolecular electron transfer rate. A MnTPyP–hydrogenase–electrode was prepared as a model system to monitor an intramolecular electron transfer, and spectroelectrochemical measurement was carried out. An intramolecular electron transfer of [Ni–Fe]-hydrogenase, which is a rate between distal [4Fe–4S] and [Ni–Fe], was measured by the developed system.