Enzyme reactions, quantum chemical cluster model approach

III. The Cluster Model Approach to Quantum Chemical Studies of Enzyme Reactions... 

Siegbahn P, Himo F (2011) The quantum chemical cluster approach for modeling enzyme reactions. WIREs Comput Mol Sci 1 323... 

Although enzymes may consist of hundreds or even thousands of amino acids, and many of these may comprise the binding site, in general only two or three residues are directly involved in catalysis (2). In favorable cases, it is possible to describe enzyme reactions accurately by modeling only a few residues, typically between 30 and 200 atoms (26). A system of this type would consist of the substrate, any required cofactors, the residues that participate directly in the reaction, and possibly one or more explicit solvent molecules. The quantum chemical cluster approach has been the subject of several informative reviews over the past decade (26-35). 

Quantum Chemical Approaches to Modelling Enzyme Reactions Cluster (or Supermolecule) Approaches... 

---