Hydrogen peroxide-dependent generation of singlet molecular oxygen by human saliva: its detection by chemiluminescence from a Cypridina luciferin analog.

By the addition of hydrogen peroxide to human saliva, chemiluminescence from Cypridina luciferin analog (CCLA) and oxygen evolution were observed. Chemiluminescence was inhibited by inhibitors of salivary peroxidase, azide and cyanide and by a singlet oxygen quencher, crocin. Deuterium oxide (99.75%) stimulated the initial increase of CCLA by 15-50% and the integrated CCLA 2.1-3.6-fold. The results suggest that the generation of singlet oxygen by peroxidase in human saliva depends on hydrogen peroxide.