Question

Consider the following statements :
(A) Coenzyme or metal ion that is tightly bound to enzyme protein is called prosthetic group.
(B) A complete catalytic active enzyme with its bound prosthetic group is called apoenzyme.
Select the correct option.

• A. Both (A) and (B) are false.
• B. (A) is false but (B) is true.
• C. Both (A) and (B) are true.
• D. (A) is true but (B) is false.

Answer 1

Answer: (A)

Enzymes could be simple or conjugated (holoenzyme). Conjugated enzymes are formed of two parts - a protein part called apoenzyme and a non - protein part called co-factor.
Co-factors are bound to the enzyme to make it catalytically active.
There are three types of cofactors : prosthetic groups, co-enzymes and metal ions.

Prosthetic groups are organic compounds and are distinguished from other cofactors in which they are tightly bound to the apoenzyme. Co-enzymes are organic compounds but their association with the apoenzyme is only transient, occurring during the course of catalysis.
A number of enzymes require metal ions for their activity which form one or more bonds in coordination with the substrate.