Question

The non - protein part of an enzyme is a
(A) Prosthetic group
(B) Coenzyme
(C) Cofactor
(D) All of the above

Answer 1

Hint: The non - protein part of an enzyme is a chemical compound that is required as a catalyst in enzyme activity. They are also known as the helper molecules of an enzyme and are made up of carbon and hydrogen.

Complete step by step answer:
Enzymes are biological molecules that help in decreasing activation energy of the reaction, so that rate of reaction can be increased.
The non - protein part of an enzyme is a Cofactor. It is a non-protein chemical compound or metallic ion that is required for an enzyme's activity. Apoenzyme and cofactor together form a holoenzyme.
Enzymes can be simple as well as complex. Simple enzymes only have a protein part in them but complex enzymes have protein as well as no protein part associated. Examples of simple enzymes are pepsin, trypsin, etc. The complex enzyme is also known as a Holoenzyme. Holoenzyme consists of a protein part and a non-protein part. The protein part of the enzyme is called ‘apoenzyme’ while the non- protein part is called ‘prosthetic group’ or cofactor.

Some common examples of holoenzymes are DNA polymerase and RNA polymerase.
Cofactors are further classified into organic and inorganic cofactors. Organic cofactors include flavin or heme and inorganic cofactors include magnesium or iron-sulfur clusters. There are many more examples of cofactors present. Organic cofactors are further classified into coenzymes and prosthetic groups.

So, the correct answer is ‘(D) All of the above’.

Note: The basic difference in them is of bonding. Prosthetic groups are tightly bonded and coenzymes are loosely bonded. Prosthetic groups consist of metal ions and coenzymes include coenzyme A, acetyl coenzyme A and many more.