Question

What are conjugated proteins? Explain their functions.

Answer 1

Conjugated proteins are different from simple proteins. Simple proteins consist only of amino acids, while conjugated proteins also have a prosthetic group attached to it.

Complete step by step solution:
A conjugated protein is defined as a protein to which another chemical group (e.g., carbohydrate) is attached by either covalent bonding or other interactions. They are formed of a proteinaceous and a non-proteinaceous prosthetic group. Hydrolysis of conjugated proteins yields amino acids along with other prosthetic groups. Depending on the type of prosthetic group, conjugate proteins are of the following types:
-Nucleoproteins: Nucleoproteins consist of Deoxyribonucleoprotein and Ribonucleoproteins. The prosthetic group attached are Deoxyribonucleic acid (DNA) and Ribonucleic acid (RNA) respectively. These conjugated proteins occur in chromosomes and ribosomes.
-Chromo proteins: Chromo proteins consist of
Flavoproteins
Haemoglobin
Cytochromes
Rhodopsin
Hemocyanin
Chloroplasts
Biliproteins
And the respective prosthetic groups attached are:
FMD, FAD
Fe
Fe
Vitamin A
Cu
Chlorophylls
Phycobilin
The occurrence of Chromo proteins is in: enzyme Erythrocyte, electron carriers of the retina, the blood of some animals, thylakoids, etc.
-Metalloproteins: The prosthetic groups attached to Metalloproteins are: Zn, Mn, Cu, Fe. The occurrence of Metalloproteins is in iron in ferritin.
-Glycoproteins: The prosthetic group attached to them is carbohydrates and they occur in the plasma membrane and cell walls.
-Mucoproteins: The prosthetic group attached to them is mucoid carbohydrates and they occur in Mucin (saliva).
-Lipoproteins: The prosthetic group attached is lipids and they occur in cell membranes.
-Phosphoproteins: The prosthetic group attached to phosphoproteins is phosphate and they occur in Casein in milk and in Vitellin in the egg.
-A conjugated protein functions in interaction with other (non-polypeptide) chemical groups attached by covalent bonding or weak interactions.

Note: Don’t confuse simple proteins with conjugated proteins. Simple proteins have no prosthetic groups attached to them.