Fig. 5.
EPR spectra of freeze-quench samples of anaerobic enzyme-substrate complex [Co-HPCD(4NC)] (purple) rapidly mixed with O2-saturated buffer under 2 atm O2 at 22 °C in 50 mM MES buffer pH 6.0, showing formation of the [Co-HPCD(4NC)O2] intermediate (red) at 2 min and subsequent decay to Co-HPCD (orange) and the extradiol ring-cleaved product after 60 min. Initial concentration of reactants were 0.5 mM [Co-HPCD(4NC)] and 2.75 mM O2. Reprinted from reference [39] with permission.