1-Aminooxy-3-aminopropane (APA) was shown to be a potent competitive inhibitor (K i = 1.0 nM) of partially purified Escherichia coli ornithine decarboxylase. APA did not inhibit S-adenosyl-L-methionine decarboxylase and spermidine synthase from E. coli. S-(5'-Deoxy-5'-adenosyl)methylthioethylhydroxylamine (AMA), which is a structural analogue of decarboxylated S-adenosyl-L-methionine, was for the first time shown to be an irreversible inhibitor of bacterial S-adenosyl-L-methionine decarboxylase and a competitive inhibitor (K i = 47 μM) of bacterial ornithine decarboxylase. AMA had no effect on spermidine synthase.
