Question

What is the role of hydrochloric acid in protein digestion?

Answer 1

Hydrochloric acid:

1. The activation of parietal cells in the gastric gland by the combined action of acetylcholine and histamine causes hydrochloric acid to be secreted.
2. It causes the contents of the stomach to be extremely acidic reducing the pH level to 2.
3. It has a variety of functions, the most important of which is to activate pepsin, which aids in the digestion of proteins in the stomach

Role of HCl:

1. An acidic environment destroys several pathogenic bacteria which could have been ingested in addition to assisting the protein digestion.
2. Hydrochloric acid (HCl) in the stomach begins protein digestion by denaturing the protein, denaturation results in the loss of the protein's function.
3. HCl also converts inactive pepsinogen to its active form, pepsin.
4. Pepsin begins breaking the peptide bonds between amino acids.
5. Hydrochloric acid operates in protein digestion in the following ways –

1. Demolishes the three-dimensional functional structure of proteins, bringing them to linear chains which increases their vulnerability to attack enzymes
2. Enhances the disintegration of proteins by converting the enzyme precursor pepsinogen to pepsin, its active form