peptic-tryptic digestion of gliadin in a manner different from mucosal homogenates of guinea-pig and normal adult human jejunum

The aetiological relationship of wheat gluten and gliadin, and some peptides obtained from them by peptic-tryptic digestion, to the clinical and small intestinal mucosal abnormalities of coeliac disease has been demonstrated in several studies (Dicke, 1950; Anderson, Frazer French, Gerrad, Sammons, and Smellie, 1952; Sheldon and Lawson, 1952; Dicke, Weijers, and van de Kamer, 1953; van de Kamer and Weijers, 1955; Schwartz, Sleisenger, Pert, Roberts, Randall, and Almy, 1957; Krainick, Debatin, Gautier, Tobler, and Velasco, 1958; Krainick and Mohn, 1959; Frazer, Fletcher, Ross, Shaw, Sammons and Schneider, 1959; van Roon and Haex, 1960, Bayless, Yardley, Norton, and Hendrix, 1962; Rubin, Brandborg, Flick, Phelps, Parmentier, and van Niel, 1962; Pittman and Holub, 1965). The mechanism of the harmful action of wheat protein and the peptides remains obscure. It has been suggested that the small intestinal mucosa of patients with coeliac disease may be deficient in peptidase activity, and therefore unable to degrade normally certain peptides derived from intraluminal digestion of wheat protein (Frazer, 1960; Rubin, 1960; Laster and Ingelfinger, 1961). Only one quantitative study of peptidase activity of small intestinal mucosa obtained from patients with coeliac disease has been reported (Messer, Anderson, and Townley, 1961). No abnormalities of peptidase activity were found when nine different synthetic peptides were used as substrates. The studies reported in this paper were carried out to determine if small intestinal mucosal homogenates obtained from patients with untreated adult coeliac disease degrade peptides derived from