Soret region CD spectra of COHbA in the presence of L35 and other effectors: COHbA alone, COHbA+L35, COHbA+L35+IHP, COHbA+L35+Cl−, and COHbA+L35+IHP+Cl−. (Inset) CD spectra of COHbA alone, COHbA+IHP, and COHbA+Cl−. (0.05 M HEPES, pH 6.35, 0.65 g % COHbA, 0.7 mM L35, 0.7 mM IHP, 70 mM Cl−, 23°C.)