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. Author manuscript; available in PMC: 2009 Nov 4.
Published in final edited form as: Chem Res Toxicol. 2008 Nov;21(11):2073–2081. doi: 10.1021/tx800140y

Figure 5. X-band electron paramagnetic resonance (EPR) spectra showing displacement of CN- by NO at heme a3 of cytochrome c oxidase.

Figure 5

Sample preparations were carried out in 0.1 M aqueous potassium phosphate buffer, pH 7.4, 1.0 mM in EDTA, 0.05% in lauryl maltoside, 22 °C, prior to freezing in EPR tubes. Recording conditions: 0.2 mW microwave power, 4 G modulation amplitude, 1 × 104 amplifier gain, 15 K sample temperature. Broken trace: partially-reduced cyanide adduct, 60 μM in enzyme, 1.0 mM in KCN, ~1 mM in Na2S2O4. Solid trace: partially-reduced cyanide adduct plus NO, 60 μM in enzyme, 1.0 mM in KCN, ~1 mM in Na2S2O4, 1.9 mM (1.0 atm) NO.