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. Author manuscript; available in PMC: 2012 Aug 6.
Published in final edited form as: Chem Res Toxicol. 2011 Nov 22;24(12):2217–2226. doi: 10.1021/tx2003323

Figure 4.

Figure 4

Generation and ESR spin-trapping of the cysteine radical. A: Complete system and simulation. The sample contained 50 mM 14N-DMPO, 10 mM cysteine, 1 mg/ml horseradish peroxidase, 10 μM H2O2, in 100 mM Chelex-treated phosphate buffer, pH = 7.4, with 100 μM DTPA. The sample was measured immediately (scan time: 167.77 s). B: As in A, but 15N-DMPO was used. C: As in A, but without cysteine. No EPR signal detected. D: As in A, but in the absence of hydrogen peroxide. A significant background signal was detected. E: As in A, but no horseradish peroxidase. No signal appeared. F: 15N-DMPO in phosphate buffer as used in A. No paramagnetic impurities are visible.