An enzyme is a catalyst, which is a chemical agent that changes the rate of a reaction without being consumed by the reaction. The reactant that an enzyme acts on is called its substrate. While the enzyme is bound to the substrate, the catalytic action converts the substrate to the product. Because of its shape, each enzyme catalyzes a specific reaction (molecular recognition). Only a certain region of the enzyme molecule actually binds to the …showed first 75 words of 552 total…

…showed last 75 words of 552 total…an allosteric site, a receptor site separate from the active site. Complex enzymes with two or more polypeptide bonds may have allosteric sites where the polypeptides join. Also, the entire unit may oscillate between two conformational states, and the inhibitor stablizes the catalytic conformation. Cooperativity, another factor, occurs when the induced-fit binding of a substrate molecule to one polypeptide subunit can change the conformation such that the active sites of all subunits are more active.