Pepsin

Pepsinogen is secreted by the main cells of the gastric glands and is activated by the action of hydrochloric acid into pepsin with a hydrolyzing protein effect. In human gastric juice, pepsin hydrolyzes proteins into glutamate, and small amounts of amino acids (tyrosine, phenylalanine) and polypeptides. Pepsinogen produced by human gastric mucosa can be divided into seven types by electrophoretic analysis, and can be divided into two groups in immunity. Pepsinogens 1 to 5 are group I and 6 to 7 are group II. The first group was only found in the fundus and gastric body glands, and the second group was also found in the pyloric and duodenal mucosa in addition to the fundus and gastric body glands. Both are present in the blood, but only pepsinogen I is in the urine, which is activated into urinary (pepsin) protease under the weakly acidic conditions of the urine.