FIGURE 9.
Kinetics of heme dissociation from the Hx-heme complex in phosphate and bicarbonate buffers. A, (○) Hx-heme (4.2 μm, pH 8.0 ± 0.2, 15 °C) in 10 mm sodium phosphate ([Na+]final = 19.3 mm), (□) 20 mm sodium bicarbonate, (◇) 10 mm ammonium phosphate ([NH4]final = 22.1 mm), and (▵) 20 mm ammonium bicarbonate. B, effect of ZnSO4 (100 μm) (denoted by filled symbols) on Hx-heme (conditions and symbols as in panel A except (▶) in 20 mm potassium bicarbonate)). C, effect of metal ions on Hx-heme in sodium phosphate buffer (conditions as in panel A). (○) no metal ion, (●) with ZnSO4 (100 μm), and (◀) with CuCl2 (100 μm).