The Metabolism of L-serylglycine O(35s)-sulphate in the Rat.

1. The preparation of potassium l-serylglycine O-sulphate and the corresponding (35)S-labelled ester is described. 2. Intraperitoneal injection of potassium l-serylglycine O[(35)S]-sulphate to rats results in about 75% of the radioactivity of the dose appearing in the urine within 48hr. Almost 72% of the radioactivity recovered in the urine was in the form of inorganic [(35)S]sulphate. 3. Analysis of urines by paper chromatography showed the presence of unchanged l-serylglycine O[(35)S]-sulphate and several other unidentified (35)S-labelled materials. 4. It has been established that micro-organisms of the gastrointestinal tract do not play any significant role in the production of inorganic [(35)S]sulphate from the injected ester. 5. l-Serylglycine O-sulphate was hydrolysed by crude dipeptidase preparations from rat kidney and intestine to yield l-serine O-sulphate and glycine as the sole products.