FLUORESCENCE QUENCHING FOR FLAVINS INTERACTING WITH EGG WHITE RIBOFLAVIN‐BINDING PROTEIN

Abstract— The effect of flavin structure variation upon the binding process of flavin to hen egg white riboflavin was studied using fluorescence methods for formylmethylflavin (FMF), riboflavin (RF) and flavomononucleotide (FMN). Measurements of flavin fluorescence intensities (steady state and phase‐sensitive) and lifetimes were performed in a variety of RBP concentrations and temperatures (4 to 40°C). No fluorescence of flavoproteins was detected, while the fluorescence of flavins was found to be quenched by RBP. The overall quenching process is dominated by the static quenching (about 88%) due to the flavoprotein complex formation in the ground state, presumably a charge transfer complex.