What is an example of globular protein?

(A) Insulin

(B) Keratin

(C) Albumin

(D) Myosin

Choose the correct answer from the options given below:

The correct answer is (A) and (C) only.

To understand why this option is correct, let us analyze the classification and examples of proteins based on their molecular shape and solubility:

1. Globular Proteins:
These proteins are formed when the polypeptide chains fold around to give a spherical or global-like shape. They are generally soluble in water. Common examples include:
- Insulin (A): A peptide hormone that regulates glucose levels in the blood, having a highly folded, compact globular structure.
- Albumin (C): A family of globular proteins, most commonly found in blood plasma, which are water-soluble and play key roles in transport and osmotic pressure regulation.

2. Fibrous Proteins:
These proteins consist of polypeptide chains lying parallel to each other, forming a fiber-like structure. They are generally insoluble in water and serve structural purposes. Common examples include:
- Keratin (B): The structural protein that makes up hair, nails, and the outer layer of skin.
- Myosin (D): A fibrous protein found in muscle fibers that plays a key role in muscle contraction.

Thus, out of the given proteins, only Insulin (A) and Albumin (C) are examples of globular proteins, making the choice (A) and (C) only the correct answer.