5'-Methylthioadenosine in urine from normal subjects and cancer patients

In an attempt to study, in human body, the metabolism of 5'-methylthioadenosine, a byproduct of the polyamine biosynthesis, we examined whether this nucleoside is excreted into urine, and, if so, whether the amount increases when the synthesis of polyamines increases. We found that 5'-methylthioadenosine is a natural nucleoside in human urine as evidenced by two separate chromatography systems as well as the analysis of the acetylated compound by gas chromatography-mass spectrometry. Preliminary study did not show the elevation of urinary 5'-methylthioadenosine level in malignant patients, suggesting that the cleaving enzyme, 5'-methylthioadenosine phosphorylase, very efficiently removes this nucleoside in vivo.