L. G. Holmes, F. M. Robbins
May 1, 1974
Citations
0
Influential Citations
8
Citations
Journal
Photochemistry and Photobiology
Abstract
Abstract— N‘‐methylnicotinamide chloride has been investigated as a quencher of the intrinsic fluorescence of tryptophyl residues in proteins. Quenching of the tryptophyl fluorescence (excitation at 305 nm) of model compounds and a select group of proteins provide evidence for a mechanism that follows the classical Stern‐Volmer relation. The apparent number of exposed tryptophyl residues was obtained in 6M guanidine hydrochloride and aqueous solution at constant pH. Evidence that quenching occurs predominantly by a collisional mechanism was obtained by comparing the equilibrium constant of the non‐fluorescent static state with the much larger quenching constant of the excited state.