Quantification of Hb-NO from human venous erythrocytes.

<p>(A) Typical EPR spectra of RBCs, frozen after blood centrifugation (a), and after 45 minutes of exposure to air (b) (diapason: 3100–3400 Gauss). (B) Final EPR spectrum of RBCs (c, gain = 6.2×10⁴), after subtraction of the model spectrum of free radicals (b), divided by the correspondent proportional scale factor, from the EPR spectrum of the initial sample frozen immediately (a). Typical EPR spectra of RBCs, frozen after incubation under low O₂ level with the NO-donor, Dea-NONOate (50 µmol/L; c, gain = 3.1×10⁴). A peak-to- peak amplitude of hf component, A(I), of the HbNO triplet structure attributed to 5-coordinate α-HbNO was used for quantitation.