Circular dichroism (CD) spectra of two major hemoglobin components (Hb), HbI and HbIV, from Oncorhyncus mykiss(formerly Salmo irideus) trout were evaluated in the range 250–600 nm. HbI is characterized by a complete insensitivity to pH changes, while HbIV presents the Root effect. Both reduced [iron(II) or oxy] and oxidized (met) forms of the two proteins were studied at different pHs, and , to obtain information about the pH effects on the structural features of these hemoglobins.
