Fig. 7.
EPR signals of the semiquinone radical in Complex I at 180 K. The systems contained 30 mg/ml of SMP in 300 μl, 150 μM CoQ1. The ubisemiquinone formation was initiated by the addition of 150 μM NADH. Spectra were obtained at a microwave frequency of 9.4121 GHz, obtaining a value of g=2.005 for the semiquinone radical.