Manometrischer Nachweis von d-Peptidasen im Serum mit Hilfe von d-Aminosäureoxydase

Abstract

The methods in use for the detn. of d-peptidase activity in which the amt. of d-peptide split is detd., are: the titration method of Grassman ,and Heide, the formol titration of Sorensen and the NH2 -N detn. of van Slyke. In these methods, pure d-peptides must be used, which are more difficult to obtain than racemic dl-peptides. In the new manometric method, the reaction mixture in the Warburg apparatus contains 0.5 ml. serum, 0.5-1 ml. M/10 dl-leucylglycylglycine and 1 ml. of 0.9% NaCl soln. The expts. are carried out 24-96 hrs. at 30[degree]. The amt. of d-leucine split off is detd. by adding d-amino acid oxidase to the mixture and measuring the O2 consumption which occurs during the deamination. The d-amino acid oxidase preparation is an acetone dried powder from pig or sheep kidneys. The d-peptidase activity in the serum of 33 normal subjects and patients is detd. The serums from patients with carcinoma show the highest d-peptidase activity, serums from patients with anemia, lymphatic leukemia, hemolytic icterus, bronchitis and tuberculosis show some activity, and serums from normal subjects and patients with nephritis and uremia show no activity.