What is an example of allosteric inhibition?

An example of allosteric inhibition involves the molecule ATP (adenosine triphosphate). In the process of glycolysis, an enzyme called phosphofructokinase catalyzes the conversion of ADP (adenine diphosphate) into ATP. When there's an excess concentration of ATP in the cellular environment, ATP acts as an allosteric inhibitor. It binds to phosphofructokinase at an allosteric site (a site other than its active site). This binding alters the enzyme's shape, slowing down the conversion of ADP to ATP. Essentially, ATP acts to regulate its own unnecessary production by inhibiting the enzyme involved in its synthesis when levels are already high.