Effect of 1-aminoproline on methionine metabolism in rats

By the intraperitoneal injection of 1-aminoproline and l-[U-¹⁴C]methionine, three unidentified radioactive compounds appeared abnormally in rat urine together with large amounts of radioactive l-cystathionine. One of them was identified as S-[l-2-(acetylamino)-2-carboxyethyl]-l-homocysteine and the other two compounds were proved to be the diastereoisomers of l-cystathionine sulfoxide. These observations indicate that the disturbance of methionine metabolism by 1-aminoproline resulted in the accumulation of l-cystathionine and its novel derivatives.