MASS-SPECTROMETRIC IDENTIFICATION OF DIPEPTIDES IN URINE OF A PATIENT SUFFERING FROM CHRONIC SKIN ULCERATION AND EDEMA

The identification of a complex ninhydrin positive mixture present in the urine of a child suffering from chronic skin ulceration and edema by direct chemical ionization mass spectrometric analysis is described. The compounds were dipeptides, of which glycylproline was the major constituent. At least 15 dipeptides were identified in the urine, most of which contained proline or hydroxyproline in the carboxy terminal position. The patient suffered probably from a defect in collagen metabolism. This hypothesis was subsequently confirmed by a grossly diminished level of prolidase in cultured fibroblasts and erythrocytes.