We describe a simple method for the determination of heme protein reduction potentials. We use the method to determine the reduction potentials for the PAS-A domains of the regulatory heme proteins human NPAS2 (Em = -115 mV ± 2 mV, pH 7.0) and human CLOCK (Em = -111 mV ± 2 mV, pH 7.0). We suggest that the method can be easily and routinely applied to the determination of reduction potentials across the family of heme proteins.
- Heme protein
- Reduction potential