[Splitting activity of gastrointestinal mucosa using paba-peptide as a substrate (author's transl)]

Splitting activity of gastrointestinal mucosa was investigated by using N-benzoyl-L-tyrosyl-p-aminobenzoicacid (PABA-peptide) in 24 surgical materials obtained from all parts of the human gastrointestinal section. The highest activity was found in the adult jejunum (2.92-4.72 mIE/cm2 intact mucosa). The splitting activity of homogenates, prepared from correspondingly sized mucosa, always was 3-5 times higher than that of the intact mucosa; it was totally inhibited by NCDC, a specific inhibitor for chymotrypsin. The solid linkage and probably also the accumulation of very stable chymotrypsin on the mucosa seem to be responsible for the low sensitivity of the Pabapeptide-test. It is possible that the specificity of this test is considerably influenced by the dependency of the linkage capacity on the morphological structure of the mucosa.