Inhibition of Photofading Reaction of Flavin Mononucleotide with Purine Bases

Abstract

An aqueous solution of flavin mononucleotide (FMN) was photostabilized by addition of caffeine and purine bases. However it was destabilized by the addition of pyrimidine bases or p-cyclodextrin, which are generally known to stabilize dyes. Caffeine and purine bases supres s the decoloration of FMN by the formation of a complex with FMN. The fluorescence intensity of FMN decreased by addition of caffeine and purine bases but did not change by addition of pyrimidine bases of β-cyclodextrin. The difference UV spectra of FMN-caffeine complex had a peak at 493nm and this absorption peak was due to the pyrazine ring of FAIN: The quinone moiety of FMN molecule is considered to be covered by caffeine but not to be covered by pyrimidine bases or β-cyclodextrin.