FIGURE 2.

Low temperature EPR spectrum of VP resting state (A) when compared with those recorded after the addition of equimolecular amounts of H₂O₂ and ferrocyanide to native VP (B) and its W164Y variant (C). All spectra were recorded at ν 9.39 GHz; modulation amplitude, 1 mT; microwave power, 2 milliwatts; modulation frequency, 100 kHz; and temperature, 20 K. EPR spectra were normalized to obtain a better resolution; real spin quantitation is reported under “Results.”