Pepsinogen and pepsin

Evidence relating to the structure and properties of swine pepsinogen and pepsin has been reviewed and used to suggest a tentative two dimensional picture of the skeleton of these two proteins. When pepsinogen, a folded single peptide chain, is converted to pepsin, there is a profound change in the physical and chemical properties of the protein. In an as yet unknown manner, except that it is initiated by a peptic cleavage of the protein chain, a single enzymic site is formed. This site is made up, quite probably, of the secondary carboxyl group of glutamic acid or of aspartic acid and a tyrosine phenol group in close proximity so that they can form hydrogen or hydrophobic bonds with the substrate in some unique manner that permits hydrolysis to occur at an accelerated rate.

Patterns of Corticosteroid and Pepsinogen Change Related to Emotional Stress in the Monkey

In association with conditioned avoidance sessions of 72 hours' duration, monkeys showed a response pattern characterized by increased levels of 17-hydroxy-corticosteroids and decreased levels of pepsinogen during the stress period, with a marked and prolonged elevation of pepsinogen levels occurring during the recovery period.

The effect of phenylbutazone (Butazolidin) on plasma pepsinogen activity

Phenylbutazone in moderate dosage has been administered to 15 patients with a variety of musculo-skeletal disorders. A rise in plasma pepsinogen activity occurred in 13, generally reaching a peak in the first week of treatment; subsequently there was a fall in spite of maintaining a constant dosage. In four of six patients an anticholinergic drug failed to prevent a rise in plasma pepsinogen activity. These findings are considered in relation to clinical observations on the time of appearance of gastrointestinal side-effects in patients receiving phenylbutazone.The interpretation of the findings is discussed, and it is suggested that the rise in plasma pepsinogen activity induced by phenylbutazone may reflect either increased peptic activity in the stomach or a damaging effect of the drug on the stomach.