Zero-link polymerized hemoglobin (OxyVita^®Hb) stabilizes the heme environment: potential for lowering vascular oxidative stress

Figures & data

Figure 1. Unfolding spectra in the Soret region of reduced, HbCO, and oxidized, metHb, forms of OxyVita^®Hbs in presence of increasing concentrations of urea at T = 37 °C, pH 7.35.

Figure 2. Size Exclusion Chromatograms (SEC) of OxyVita^®C HbCO (top) and OxyVita^®metHb (bottom). Wavelength detection was at 280 nm. Column used was 60 cm long ×0.5 cm diameter with Fractogel (20–40 μm) with a flow rate of 0.5 mL/min. Mobile phase was 0.05M phosphate buffer at pH =7.4.

Figure 3. Unfolding spectra in the Soret region of the met forms of myoglobin (monomeric), bovine Hb (tetrameric), and OxyVita^®Hb (zero-linked polymeric) in the presence of urea at T = 37 °C, pH 7.35.

Figure 4. Unfolding transitions in the Soret wavelength maximum of the oxidized met forms of Mb, BvHb, OxyVita^®Hb, and the reduced (CO) form of OxyVita^®Hb in the presence of increasing concentrations of urea at T = 37 °C, pH 7.35.

Figure 5. Comparison of the changes in the Soret wavelength maximum for the met forms of Mb, BvHb, and OxyVita^®Hb in the presence of increasing concentrations of urea at T = 37 °C, pH 7.35.

Table 1. Denaturation midpoint (D_1/2) at T = 37 °C in presence of urea.

Reduced (heme-Fe^+2)
OxyVita HbO2 (17 MDa, polymeric)	6.9 M
OxyVita HbCO (17 MDa, polymeric)	6.9 M
Oxidized (heme-Fe^+3)
OxyVita MetHb (17 MDa, polymeric)	6.3 M
Bovine MetHb (64 kDa, tetrameric)	5.4 M
Metmyoglobin (17 kDa), monomeric)	5.4 M

Figure 6. Changes in the Soret wavelength maximum for the reduced forms (CO and Oxy) and oxidized form of OxyVita^®Hbs in the presence of increasing concentrations of urea at T = 37 °C, pH 7.35.

Figure 7. Oxidative pathways associated with heme exposure.