What Is a Non-Allosteric Enzyme?

Non-allosteric enzymes are a subset of enzymes that do not have an allosteric binding site in addition to the active site. These enzymes change in function solely due to the binding of a substrate to the active site and do not require the binding of allosteric modulators.

A non-allosteric enzyme is any enzyme that is not an allosteric enzyme. All enzymes have an active site, which binds a substrate and causes the enzyme to function in a certain way. Allosteric enzymes also contain an allosteric site, which is bound by allosteric modulators. The binding of this second site on allosteric molecules either enhances or impairs the function of the enzyme. Non-allosteric enzymes do not have this second binding site and, therefore, are usually completely active or completely inactive.

Non-allosteric enzymes serve as regulatory enzymes. Biochemical pathways are often initiated or continued through the activation of enzymes, such as hormone production. Non-allosteric enzymes and allosteric enzymes are functionally separate in these pathways, but they are equally important. Allosteric enzymes are modulated when the allosteric site is bound so that their level of activation or inactivation can be influenced. Non-allosteric enzymes have one binding site and therefore are simply active or inactive, allowing them to heavily influence protein production when necessary.