Light-induced oxidation of tryptophan and histidine. Reactivity of aromatic N-heterocycles toward triplet-excited flavins.

@article{Huvaere2009LightinducedOO,
  title={Light-induced oxidation of tryptophan and histidine. Reactivity of aromatic N-heterocycles toward triplet-excited flavins.},
  author={Kevin Huvaere and Leif H Skibsted},
  journal={Journal of the American Chemical Society},
  year={2009},
  volume={131 23},
  pages={8049-60}
}
Mechanisms of flavin-mediated photooxidation of electron-rich amino acids tryptophan and histidine were investigated for aqueous solutions. Indole, representing the tryptophan side chain in proteins, reacted at nearly diffusion controlled rates (k approximately 2.7 x 10(9) L mol(-1) s(-1) at 293 K) with the triplet-excited flavin state, but reactions of imidazole (and histidine) were significantly slower (k < 2.0 x 10(8) L mol(-1) s(-1)) as determined by laser flash photolysis. Oxidation rates… CONTINUE READING