5'-Deoxy-5'-methylthioadenosine (MTA) is an intermediate in the generation of adenine and methionine that is produced by the decarboxylation of S-adenosylmethionine. This nucleoside is a potent agonist of adenosine receptors (Kis = 0.15, 1.13, 13.9, and 0.68 μM for A1, A2A, A2B, and A3, respectively). At higher concentrations, MTA inhibits several enzymes, including protein carboxylmethyltransferase (Ki = 41 μM), S-adenosylhomocysteine hydrolase, SET methyltransferases, and spermidine and spermine synthases.
