Rate constants of quenching of the fluorescence of pterins by the iodide anion in aqueous solution

Abstract

The fluorescence of various pterins (6-methylpterin, 6-hydroxymethylpterin, 6-formylpterin, and 6-carboxypterin) was quenched using iodide in neutral, aerated neutral phosphate buffer. Stern-Volmer plots and the fluorescence lifetimes were used to determine fluorescence quenching rate constants that approach the rate of diffusion. Given that pterin photoproducts have been detected in the human skin exposed to UV radiation, biological implications of the high rate constants are discussed.