Question

Describe how allosteric regulators may inhibit or stimulate the activity of an enzyme and how this can be used by the cell to regulate metabolic pathways. (in paragraphs)

Answer 1

Enzymes are protein that can be regulated by specific regulatory molecules called allosteric regulators. These regulators act as both enzyme activators and as well as inhibitors. The regulatory molecules have different subunits that can bind on the enzyme other than the active site. The regulator binding site is therefore known as allosteric site. The binding of allosteric site either activates o inhibits the enzyme activity depending on the nature of allosteric regulator molecule.

When the inhibitor molecules are bind at allosteric site, the active sites of protein subunits of allosteric enzymes undergo conformational changes so that the enzyme becomes less active or can be inhibited completely.

When an enzyme activator is bound at the allosteric site, they are capable of increasing the function oractivity of active site of the enzyme. The coordination between the allosteric activator and enzyme enhances the efficiency of enzyme activity due to process of cooperativity. Allosteric enzymes are commonly found in metabolic pathways that are constitutively under regulation. The best known allosterically regulated protein is hemoglobin molecule. The binding of hemoglobin to oxygen is allosterically regulated. Inhibitor molecules compete with oxygen for binding to hemoglobin. Some allosteric activators enhance the oxygen binding to hemoglobin.