Figure 3.
Evaluating the labeling kinetics of sfGFP-151-5HTP by CRACR using the associated fluorescence quenching. A) Fluorescence spectra of a reaction mixture consisting of 5 μM sfGFP-151-5HTP and 50 μM 4CDZ at room temperature in 100 mM phosphate buffer over time. B) Fluorescence intensity of the same reaction monitored over time yields the pseudo-first order rate constant. (Inset) Plotting the resulting pseudo-first order rate constant at various 4CDZ concentrations against the corresponding [4CDZ] provides the second order rate constant (k2) of the labeling reaction.