Protein-ligand interactions binding order

The thermodynamic analyses most often used, particularly fhe van t Hoff mefhod, require that measurements be made at steady-state conditions. In the case of radioligand binding determination of equilibrium constants, fhe time required for fhe protein-ligand interaction to reach steady state depends on fhe incubation temperature, and, therefore, the equilibrium constant must be determined for each temperature studied. For the most accurate results, fhe determination needs to be made at more than two temperatures in order to detect non-linearity. The integrated form of the van t Hoff equation takes fhe simple form fhat is commonly used only if ATT and AS° for the interaction are not temperature dependent otherwise, non-linearity in the van t Hoff plot can arise. Meaningful information can StiU be obtained in such cases, but more complex analysis is required. 

Biotin binds very tightly to the tetrameric protein avidin (also streptavidin and neutravidin], with a dissociation constant in the order of 10, which is one of the strongest known protein-ligand interactions, the strength being approximately due to the the... 

In particular, steady-state and time-resolved fluorescence as well anisotropy are powerful tools for studying function and conformation of sensitizer in vesicular membrane systems, in order to provide structural information on sensitizer-colloid binding or to evaluate protein-ligand interactions. 

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