Protein-ligand interactions QSAR studies

The dissociation constant is commonly used in QSAR studies to describe the affinity between a ligand (such as a drug) and a protein, that is, how tightly a ligand binds to a particular protein. Ligand-protein affinities are influenced by noncovalent intermolecular interactions between the two molecules such as hydrogen-bonding, electrostatic interactions, hydrophobic, and Van der Waals forces. 

Tuppurainen, K., Viisas, M.. Perakyla, M. and Laatikainen, R. (2004) Ligand intramolecular motions in ligand-protein interaction ALPHA, a novel dynamic descriptor and a QSAR study widi extended steroid benchmark dataset. /. Comput. Aid. Mol. Des., 18, 175-187. 

Due to the definition of the method, many CoMFA studies and related 3D QSAR analyses, where GRID and other molecular fields are implemented in a CoMFA-like model, deal with the quantitative description of ligand-protein interactions, like enzyme inhibition, e.g. 

---