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. Author manuscript; available in PMC: 2009 Aug 13.
Published in final edited form as: J Am Chem Soc. 2008 Jul 18;130(32):10780–10787. doi: 10.1021/ja803083z

Figure 3.

Figure 3

EPR spectra of 10 µM aTAM5 radical in 1.5 mM Na-pyrophosphate buffer under nitrogen atmosphere, 37 °C at pH values 9.40 (a), 8.20 (b), and 6.00 (c). Spectral parameters: microwave power, 0.63 mW; time constant, 163.84 ms; conversion time, 240.0 ms; sweep time, 245.76 s; modulation amplitude, 0.1 G; sweep width, 5 G; number of points, 1024. Dotted lines represent the calculated spectra with peak-to peak line widths, ΔHL = 96 mG, ΔHG = 95 mG, and following hfs constants: (a) aN = 0.78 G, aD1(CD2) = 0.15 G, aD2(CD2) = 0.30 G; (c) aN = 0.99 G, aD1(CD2) = 0.15 G, aD2(CD2) = 0.17 G, aH(NH+Et2) = 0.15 G. Calculated spectrum b is a superposition of calculated spectra a (68%) and c (32%) yielding corresponding pKa = 7.9 for the protonation of the amino group.