Pepsinogen regulation

Morrow B, Srikantha T, Soil DR Transcription of the gene for a pepsinogen, PEPl, is regulated by white-opaque switching in Candida albicans. Mol Cell Biol 1992 12 2997-3005. 

Protein digestion begins in the stomach, where a proenz5nme called pepsinogen is secreted, autocatalytically converted to Pepsin A, and used for the first step of proteolysis. However, most proteolysis takes place in the duodenum as a consequence of enzyme activities secreted by the pancreas. All of the serine proteases and the zinc peptidases of pancreatic secretions are produced in the form of their respective proenzymes. These proteases are both endopeptidase and exopeptidase, and their combined action in the intestine leads to the production of amino acids, dipeptides, and tripeptides, all of which are taken up by enterocytes of the mucosal wall. How preoteolytic enzymes are regulated ... 

Although much attention has been focused on the regulation of acid secretion and pepsinogen, the mechanisms responsible for the secretion of intrinsic factor and its subsequent role in the absorption of cobalamin are vital to the organism. Indeed, it might be said that without adequate intrinsic factor secretion or cobalamin ingestion, all other secretory processes of the stomach would be defunct within a 3- to 5-year period as the organism perished. 

Yasugi S. Regulation of pepsinogen gene expression in epithelial cells of vertebrate stomach during development. Int J Develop Biol 1994 38 273-279. 

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