Cystinuria: Metabolism of the Disulfide of Cysteine and Homocysteine*

This is the authors' abstract. We don't add key points for this paper.

The isolation and identification of the asymmetrical disulfide of L-cysteine and L-homocysteine, hereafter referred to as were previously described (1). At that time the amino acid had been found only in the urine of patients with cystinuria. This paper attempts to explain the origin and significance of the mixed disulfide. In approaching this work, I first assessed the natural occurrence of mixed disulfide. To increase the compound's sensitivity to detection in a complicated area of the chromatogram, it was rendered radioactive by the administration of L-methionine-S35. The radioactive mixed disulfide was isolated from the urine of a patient with cystinuria after he was fed L-methionine-S35, and the specific activities of the two sulfur atoms were compared to each other and to cystine sulfur. The mixed disulfide, synthesized with S35 was administered to a patient with cystinuria, and its fate was studied. Finally, to define the role of the kidney in metabolism of the compound, concentrations in renal venous blood were compared with those in arterial blood.