Question

The example of phosphoprotein is
A. Mucin
B. Fibrinogen
C. Casein
D. Myosin

Answer 1

Hint: Phosphoprotein is a conjugate of simple protein and phosphate group. It is found in milk protein which nourishes infants.

Complete answer: Proteins are very important part of our diet. Why is that so? Because it is an important part of our system- enzymes, immunoglobulins, haemoglobin, transcription factors – everything is protein.
Proteins are made up of amino acids. Amino acid residues joined by peptide bonds to form polypeptide chains. The chains further get folded into secondary, tertiary, and quaternary structures- these are called proteins.
Proteins may be of these types: globular, fibrous, and membrane proteins.
They may be complete or incomplete proteins (according to the nutrition they provide). Based on the source, proteins may be differentiated as plant proteins and animal proteins.
Phosphoproteins are conjugate proteins which get modified by the attachment of phosphate groups. Such a protein is casein (milk protein).

So, the correct answer is C. Casein

Note: When proteins are covalently attached to other chemical groups, they are called conjugate proteins. These are basically the complex structure of a simple protein and a non-protein component linked by covalent interaction. Another conjugate protein is a glycoprotein.