Chemiluminescent oxidation of ribose catalyzed by horseradish peroxidase in presence of hydrogen peroxide

Abstract

The reaction of ribose with horseradish peroxidase in the presence of H 2O 2 is accompanied by light emission. The detection of horseradish peroxidase Compound II (FeO 2+) indicates that the enzyme participates in a normal peroxidatic cycle. Hydrogen peroxide converts horseradish peroxidase into Compound I (FeO 3+) which in turn is converted into Compound II by abstracting a hydrogen atom from ribose forming a ribosyl radical. In aerated solutions oxygen rapidly adds to the ribosyl radical. Based on the spectral characteristics and the enhancement of the chemiluminescence by chlorophyll-a, xanthene dyes, D 2O and DABCO, it is suggested that the excited species, apparently triplet carbonyls and 1O 2, are formed from the bimolecular decay of the peroxyl radicals via the Russell mechanism.