[New 5'-sulfurated nucleosides as inhibitors of the biosynthesis of polyamines].

The inhibitory effect of the deaminated analogs of S-adenosyl(5')-3-methylthiopropylamine on spermidine synthase (EC 2.5.1.16.) from E. coli, AdoMet decarboxylase (EC 4.1.1.50.) from human placenta and E. coli and AdoMet lyase (EC 3.3.1.-) from rat liver have been reported. 5'-isobutylthioadenosine, a new powerful antiproliferative drug has been assayed as substrate of MTA phosphorylase (EC 2.4.2.1). The apparent Km is 1,8x10(-5) M. The inhibitory effect of 5'-isobutylthiadenosine on AdoMet lyase and spermidine synthase was also demonstrated.