Biology Question on Digestion and absorption

Question

Which one of the following enzymes initials protein digestion?

Answer 1

Solution

The gastric juice is secreted in considerable amount, with pH range of $1-3.5$ . It contains $97-99 \%$ water, $0.2$ to $0.5 \% HCl$ and rest mucous, salt and enzymes. Pepsin is one of the major enzyme present in the gastric juice. Pepsin is secreted as pepsinogen (inactive form) converted into active form of $HCl$ endopeptidase in nature, ie, does not require any terminus for attack, works on interstitial sites. Converts protein molecules (especially of collagen) into proteoses, peptones and ultimately into large polypeptides.