Chemical stability denaturation experiments.

<p><b>A</b>. Kinetics of retinal hydrolysis of the four chromoproteins by hydroxylamine hydrochloride. The molar ratio protein/NH₂OH was 1∶4000. The measurements were done in 5 mM phosphate buffer pH 7.5 in the dark. <b>B</b>. Absorbance spectra of the denaturation process (upper panels) compared to the minus second derivative of the absorbance spectra (lower panels) for each reconstituted protein (as indicated in the figure). For sake of clarity, initial, mid and final spectra of the reaction are plotted with thicker lines.