Question

Enzyme capable of changing their shape is called
(a) Apoenzyme
(b) Coenzyme
(c) Allosteric enzyme
(d) Co-factor

Answer 1

Hint: Protein binding sites called allosteric sites are present in the enzymes which alter their shape when an organic molecule binds to the enzyme. These enzymes can enhance or reduce the enzyme activity.

Complete answer:
Enzymes consist of binding sites, for an enzyme if an effector molecule comes and binds at the binding site and if this results in a conformational change in the shape of the enzyme. Enzymes with this feature or property are called allosteric enzymes. The binding site in allosteric enzymes is called the allosteric site.

Additional Information: - The inactive enzyme which is activated by the addition of organic or inorganic molecules is called an apoenzyme which is a protein part of the enzyme.
- A non-protein or an organic molecule that binds to the enzyme to activate is called a coenzyme
- In general, enzymes are nothing but proteins composed of several polypeptide chains. However, there are a number of cases where the enzyme contains a non-protein part called cofactors that are bound to the enzyme to make it catalytically active.
- These cofactors are of three types namely prosthetic groups, coenzymes, and metal ions
- The organic compounds that are distinguished from cofactors are called prosthetic groups. They bound tightly to the apoenzyme
- The organic compounds that bound to the apoenzyme only during the catalysis are called coenzymes.
- The catalytic of an enzyme is lost when a cofactor is removed from the enzyme.
- allosteric enzymes alter their shape according to proteins to be attached to increase the enzymatic activity of that enzyme.
So, the correct answer is ‘allosteric enzyme’

Note: -Haem acts as a prosthetic group during the breakdown of hydrogen peroxide to water and oxygen.
-Niacin is the cofactor present in nicotinamide adenine dinucleotide(NAD).
-The protein part of the enzyme is apoenzyme and the non-protein part of the enzyme is a cofactor.