Biology

A gastric gland is a tubular structure in the vertebrate stomach that

secretes gastric juices. The gastric glands have three types of cells that secrete

different components of the gastric juice. One of them is being a chief cell, which

is a rust color and is an inactive form of the digestive enzyme Pepsin. Pepsin

begins the digestion of proteins in food. Pepsin is a Peptidases, which is an

enzyme that breaks peptide bonds of proteins.

Pepsin is found in the mucosal lining of the stomach that breaks down

the protein in the food we eat. A protein is an organic compound that consists of

aminio acids joined by peptide bonds. Pepsin is one of three principal protein-

degrading enzymes in the digestive system the other two being chymotrypsin

which catalyzes the hydrolysis of peptide bonds and trypsin that acts with the

other proteins to break down dietary protein molecules to their peptides and

amino acids which will be absorbed by the intestinal lining. Pepsin is synthesized

in an inactive form in the stomach lining; it is necessary to convert the inactive

enzyme and to maintain the optimum acidity (pH 1-3) for pepsin function.

Secreting pepsin in the inactive form of pepsinogen helps to protect the

cells of the gastric glands, and mucus helps protect the stomach lining from both

pepsin and acid. Pepsinogen and HCl are secreted into the interior of the gastric

gland. Then HCl converts pepsinogen into pepsin. Then pepsin activates more

pepsinogen starting a chain reaction. Pepsin begins chemical digestion of