Question

Which of the following is a substrate of pepsin?
A. Proteins
B. Fats
C. Carbohydrates
D. Vitamins

Answer 1

Pepsin is an endopeptidase in nature and it breaks down the proteins into smaller peptides.
It is generally produced in the chief cells of the stomach lining and is one of the main digestive enzymes found in the digestive systems of humans and many other animals.
It helps us to digest the proteins that are present in food.

Complete answer: Pepsin is a protein splitting enzyme that splits proteins into smaller chains called proteases and peptones.
The main and very first site of protein digestion in the stomach.
In the stomach, the pepsin is secreted as an inactive zymogen which further forms pepsinogen and gets converted into active pepsin when exposed to gastric hydrochloric acid.
It is generally regarded as one of three principal proteases in the human digestive system, the other two are named chymotrypsin and trypsin.
During the process of digestion, these enzymes, each of which is specialized in providing links between special types of amino acids and they collaborate to break down dietary proteins into their components, they are peptides and amino acids, which can be readily absorbed by the small intestine.
The cleavage specificity of pepsin is broad, but some amino acids like tyrosine, phenylalanine, and tryptophan increase the probability of cleavage.

So, the correct option is option A. Protein.

Note: Pepsin is one of the primary causes of mucosal damage during laryngopharyngeal reflux.
Pepsin remains in the larynx whose pH 6.8 following a gastric reflux event.
While enzymatically inactive in this environment, pepsin would remain stable and could be reactivated upon subsequent acid reflux events.