Effect of adenosylhomocysteine and other analog thioethers on a prokaryotic tRNA (guanine-7)-methyltransferase

Giovanni Paolella, Gennaro Ciliberto, Cinzia Traboni, Filiberto Cimino, Francesco Salvatore

Research output: Contribution to journalArticlepeer-review


S-Adenosylhomocysteine (SAH), a potent inhibitor of methyltransferases, and several thioethers structurally related to SAH, have been tested as potential inhibitors of tRNA (guanine-7)-methyltransferase from Salmonella typhimurium. The tested compounds are l-, d-, dl-S-adenosylhomocysteine, S-adenosylcysteine, methylthioadenosine, butylthioadenosine, thioethanoladenosine, isobutylthioadenosine, S-inosylhomocysteine, and methylthioinosine. Among them the highest inhibitory activity has been shown by SAH (Ki = 8 μM), whereas butylthioadenosine, isobutylthioadenosine, and thioethanoladenosine are almost inactive as inhibitors. The other compounds inhibit the enzyme with Ki values ranging between 400 and 800 μm. From these data it is possible to evaluate the importance of the -NH2 and -COOH groups of the substrate in the binding to the enzyme molecule, as well as other features such as the chirality at the α-carbon atom and the length of the hydrocarbon chain connecting the -NH2 and -COOH groups to the aromatic ring of adenosine. The aminic group of the adenosine is also critical, because S-inosylhornocysteine and methylthioinosine are poorer inhibitors in comparison with SAH and methylthioadenosine.

Original languageEnglish
Pages (from-to)149-154
Number of pages6
JournalArchives of Biochemistry and Biophysics
Issue number1
Publication statusPublished - 1982

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology


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