Enzyme that begins the breakdown of proteins in the stomach?

Enzyme that begins the breakdown of proteins in the stomach?

• A. Pepsin
• B. Amylase
• C. Lipase
• D. Trypsin

Answer: (A)

Protein digestion begins in the stomach with a protease that is activated by the stomach’s acidic environment. This enzyme is produced as an inactive precursor, pepsinogen, by the stomach’s chief cells and is activated to pepsin when exposed to hydrochloric acid released by the parietal cells. Pepsin then cleaves peptide bonds within protein molecules, starting the breakdown into smaller polypeptides in the harsh acidic conditions of the stomach. Amylase digests carbohydrates, lipase digests fats, and trypsin—another protease—acts in the small intestine after the stomach, so they don’t initiate protein digestion in the stomach.

Protein digestion begins in the stomach with a protease that is activated by the stomach’s acidic environment. This enzyme is produced as an inactive precursor, pepsinogen, by the stomach’s chief cells and is activated to pepsin when exposed to hydrochloric acid released by the parietal cells. Pepsin then cleaves peptide bonds within protein molecules, starting the breakdown into smaller polypeptides in the harsh acidic conditions of the stomach. Amylase digests carbohydrates, lipase digests fats, and trypsin—another protease—acts in the small intestine after the stomach, so they don’t initiate protein digestion in the stomach.