8.2.1 Mechanism of Enzyme Action

8.2.1 Mechanism of Enzyme action

Explanations of how enzymes function as catalysts in biochemical systems are based on the concepts of an enzyme active site and enzyme substrate complex formation.

                                   E+S  ---- ES  ------P    

The active site is the relatively small part of an enzyme’s structure that is actually involved in catalysis.

The active site in an enzyme is a three-dimensional entity formed by groups that come from different parts of the protein chain(s); these groups are brought together by the folding and bending of the protein. The active site is usually a “crevice like” location in the enzyme.

 

Catalysts offer an alternative pathway with lower activation energy through which a reaction can occur. In enzyme controlled reactions, this alternative pathway involves the formation of an enzyme substrate complex as an intermediate species in the reaction when a substrate binds to the active site of an enzyme. Within the enzyme substrate complex, the substrate encounters more favorable reaction conditions than if it were free. The result is faster formation of product.

Last modified: Monday, 30 January 2012, 7:17 AM