PEROXIDASE-CATALYZED COOXIDATION OF INDOLE-3-ACETIC-ACID AND XANTHENEDYES IN THE ABSENCE OF HYDROGEN-PEROXIDE

The effect of xanthene dyes on the chemiluminescence from the aerobic indole-3-acetic acid (IAA) oxidation, catalyzed by horseradish peroxid ase (HRP), was studied. The rate of IAA oxidation and dye destruction were controlled. It was found that the addition of dyes to the IAA/HRP /O2 system resulted in: (i) the appearance of emission in the region o f dye fluorescence, (ii) an increase of the total chemiluminescence in tensity, (iii) a decrease of the emission duration, (iv) the accelerat ion of IAA oxidation, and (v) slow bleaching of the dyes. The experime ntal results lead to the conclusion that all spectral and kinetic vari ations of the chemiluminescence from the IAA/HRP/O2 system which are c aused by the addition of xanthene dyes, are the result of IAA-dye co-o xidation. Earlier published reports regarding energy transfer from ele ctronically excited species, generated in the IAA/HRP/O2 system, to th e xanthene dyes seem to be erroneous.