Neubauer and Fischer,1 in 1909, proposed the use of glycyltryptophan as a reagent for the estimation of peptolytic activity and applied it to the diagnosis of carcinoma of the stomach. The test consisted in mixing glycyltryptophan with a portion of the filtered gastric juice obtained after the usual test breakfast, incubating for twenty-four hours, and then testing with bromin vapor for the rose-violet color of free tryptophan.
Their conclusions were as follows :
There exists in carcinomatous stomach contents a ferment which, contrary to pepsin, will split glycyltryptophan.
This ferment is destroyed by an acidity of .36 per cent. HCl.
The presence of this ferment may be of diagnostic value.
Their report was accepted with widely divergent criticism. Lyle and Kober,2 Pechstein,3 Oppenheimer4 and others, considered it of value. Ley,5 Ehrenberg,6 Sanford and Rosenbloom,7 etc., believed it valueless. Several authors described
FRIEDMAN JC, HAMBURGER WW. THE VALUE OF EDESTIN AND PEPTONE IN THE DIAGNOSIS OF CANCER OF THE STOMACH. Arch Intern Med (Chic). 1913;XII(3):346–355. doi:10.1001/archinte.1913.00070030103010