| Assay Method Information | |
| | Fluorescence Direct Binding Protocol |
| Description: | Determination of the affinities of compounds to protein containing one or more tryptophan is measurable by monitoring the fluorescence emission in direct mode. The measurements depending on the protein available amounts are performed either manually in a cuvette on ISS-PC1 photon counting spectrofluorometer or automatically in well plates on a fluorescence plate reader device. Fluorescence titrations are performed at 20° C. in the chosen binding assay buffer by using a defined constant protein concentration against ligand concentration variations. Small aliquots of known ligand concentration solubilized in DMSO were added and the fluorescence, excited at 280 nm, was recorded at 340 nm. The fluorescence intensity was corrected for protein dilution and for the filter effect (Birdsall et al.). The corrected fluorescence intensity was plotted against the ligand concentration and fitted using a four-parameter sigmoidal function, from which the equilibrium dissociation constant Kd was computed using the law of mass action assuming a 1:1 protein-ligand complex |
| Affinity data for this assay | |
|---|---|
| If you find an error in this entry please send us an E-mail | |