Raman spectrum of fully reduced flavin

Protein-flavin interactions modify the chemistry of the flavin, 'tuning' it to its biological function. In order to understand protein interactions with reduced flavins, the Raman spectrum of reduced FAD was recorded at pH values where the reduced isoalloxazine is neutral and anionic. Reduced isoalloxazine is a weaker Raman scatterer than oxidized isoalloxazine by at least an order of magnitude in both ionization states. Substitution of exchangeable protons for deuterium, the effect of ionization and DFT calculations allowed the assignment of the observed Raman bands to normal modes of vibration. Copyright (C) 2004 John Wiley Sons, Ltd.