Chromatographic evidence on the occurrence of thiotaurine in the urine of rats fed with cystine.

Rats fed a diet supplemented with L-cystine excrete in the urine taurine, hypotaurine (l-3), and possibly cystamine disulfoxide (4)) although the excretion of the last mentioned compound is not certain (3). It was recognized earlier (1) that paper chromatograms of the urine of these rats showed another ninhydrin-positive spot which moved more rapidly than did taurine incollidine-lutidine solvent. The natureof thenew compoundwas not investigated because it did not appear in all chromatograms and because it represented only a small fraction of the sulfur compounds excreted. More recently, an unknown cystine metabolite has been observed by chromatography by Awapara in the organs of rats treated with injections of S%ystine (5). We have now accumulated evidence for the identification of the new compound as the thiosulfonate analogue of taurine, aminoethylthiosulfonate (NH2-CH*-CH*--S02-SH). Following Sorb0 (6), the term thiotaurine will be retained for this compound.