Abstract
Five dipeptidase activities in the mucosa of the gastrointestinal tract from 25 patients between 22 and 80 years of age were determined. The influence of pH and bivalent metal ions on the various activities was studied. Equally low activities were found in the stomach and the large intestine. In the small intestine, low activities were found in the mucosa of the proximal duodenum, whereas that of the jejunum and ileum contained high activities. The results have been discussed in relation to our previous informa‐ tion about the intestinal dipeptidases.