Question

Which of the following is/are examples of simple proteins?
A. Albumin
B. Globulin
C. Glutadin
D. All of the above

Answer 1

Hint: Simple proteins are those which are made of amino acid units only and are joined by the peptide bond. Upon hydrolysis, they yield a mixture of amino acids and rarely some carbohydrates, present in small amounts.

Step-by-Step Solution:
Let us first define what a simple protein really is and how it can be identified.
Simple proteins are made up of amino acid subunits joined together by peptide bonds. When hydrolysed by enzymes, simple proteins yield only the amino acids from which they are composed of.
With this definition in mind, let us now examine each option one at a time and see whether they fit this definition.
Albumin is an egg protein which is globular in structure with polar groups placed at the protein surface. It is present in the clear liquid which is present inside the egg. It consists of 90% water which has about 10% proteins dissolved in it.
It is a simple protein as it yields only amino acids upon hydrolysis, thereby fitting the definition of simple proteins.
The globulins are a family of globular proteins that have higher molecular weights than albumins and are insoluble in pure water but dissolve in dilute salt solutions. Some globulins are produced in the liver, while others are made by the immune system.
Similar to albumin, globulins are simple proteins as they yield only amino acids and some carbohydrates upon hydrolysis, thereby fitting the definition of simple proteins.
The following is the obtained structure of -globulin obtained at nanogram levels.

Similarly, with Glutadin, it can be classified as a simple protein as it yields only amino acids upon hydrolysis, thereby fitting the definition of simple proteins.
Therefore, by this analysis , we can safely conclude that the answer to this question is d) All of the above.

Note: Before you solve this question, you must be conceptually very clear about the properties and structures of amino acids and proteins. Another very important point of consideration is that do not mix up the simple protein Glutadin with the amino acid Glutamine as these ase two very different biomolecules.