Question

Differentiate between prosthetic groups and coenzyme, give one example for each.

Answer 1

Hint: Enzymes are biological catalysts used to catalyse the chemical reactions that take place inside our body. Enzymes work upon molecules known as substrates and convert them to products. All metabolic processes require enzymes.

Complete answer:
Enzymes are proteins which are necessary for controlling the metabolic and chemical reactions taking place inside our body. Enzymes need helper molecules called cofactors which are of two type prosthetic groups and coenzymes.
Prosthetic groups are non-amino acid components and a part of heteroproteins or conjugated proteins. They can be organic like vitamins, sugar or lipids and inorganic in the form of metal ions. They bind tightly with the proteins or enzymes with the help of strong covalent bonds. The heme group of haemoglobin is the prosthetic group. They are required in the catalysis activity of enzymes.
Coenzymes are small organic molecules that help enzymes as intermediate carriers of electrons, functional groups, and atoms. They are mostly derived from water soluble vitamins like vitamin B. Most common coenzymes are NAD (Nicotinamide adenine dinucleotide) , thiamine, pyridoxine, folic acid, biotin, FAD etc.

Difference between prosthetic group and co-enzymes :

Prosthetic groups	Coenzymes
1. Can be organic or inorganic.	1. Are always organic.
2. Type of cofactors that bind tightly to the enzymes.	2. Type of cofactors that loosely bind to the enzyme.
3. Help the enzyme in catalysis by binding with it.	3. Help the enzyme in catalysis by transforming it.
4. Bind to the enzyme covalently that is why it is difficult to separate from the enzyme.	4. Can be easily separated from the enzyme as they are loosely bound with it.
5. Example – Metal ions, heme group of haemoglobin .	5. Example – Biotin, FAD (Flavin Adenine Dinucleotide), Folic acid.

They have some similarities too as both of them are the non-protein part of the enzyme, assist the enzyme in its functioning and can be organic molecules attached to the enzymes.

Note: Haemoglobin is the pigment molecule that is responsible for the red colour of the red blood cells and is responsible for carrying oxygen. Heme is the most important part of haemoglobin that is made up of magnesium ions and is a prosthetic group.