Resolution of amino thiols in time-resolved luminol chemiluminescence catalyzed by peroxidases

Hydrogen peroxide (H2O2) formed during the course of the Cu(II)-catalyzed oxidation of amino thiols with oxygen was detected by the Arthromyces ramosus peroxidase-catalyzed luminol chemiluminescence (CL) method. Two peaks appeared in the CL response curve in the catalytic oxidation of both cysteine (CySH) and gluthathione (GSH) and in that of both cysteamine and GSH. The resolution of two peaks corresponding to CySH and GSH was better than that corresponding to cysteamine and GSH. Only a strong CL flash appeared in the catalytic oxidation of both CySH and cysteamine. The differences in the resolution of two peaks of amino thiols could be explained on the basis of the differences in the stability constants between Cu(II) and amino thiols.