Table 2.

Second-order rate constants *, k (M⁻¹s⁻¹) of HSA-NIT reduction in PBS (pH 7.4) at 25 °C by EPR and T₁ relaxation time measuring.

Sample	Method	kinit, M−1s−1	k“free” NIT, M−1s−1
HSA-Me	EPR	0.044 ± 0.006	0.097 [100], 0.063 [98]
	T1-meas.	0.027 ± 0.005
HSA-Me-Mal	EPR	0.041 ± 0.006
HSA-Me/Me-Mal	EPR	0.043 ± 0.008
	T1-meas.	0.033 ± 0.006
HSA-Et	EPR	0.0019 ± 0.0005	0.001 [98], 0.002 [101]
	T1-meas.	0.0015 ± 0.0001
HSA-Et-Mal	EPR	0.0016 ± 0.0004
HSA-Et/Et-Mal	EPR	0.0015 ± 0.0004
	T1-meas.	0.0007 ± 0.0001

* The kinetics of nitroxide reduction in the presence of ascorbate/glutathione are summarized in Figures S7 and S8.