Stabilization of S-adenosylmethionine decarboxylase by aminoguanidine

Aminoguanidine, an inhibitor of copper-containing amine oxidases, is often used in cell culture studies to prevent the oxidation of added polyamines or their derivatives by the amine oxidase present in bovine serum. However, in the present study, we demonstrate that aminoguanidine, besides affecting the degradation of polyamines, may affect one of the important regulatory enzymes in the biosynthesis of polyamines, namely S-adenosylmethionine decarboxylase (AdoMetDC). Aminoguanidine was shown to induce a 2-3-fold increase in the AdoMetDC levels in L1210 cells. This increase was fully explained by a stabilization of the enzyme, probably caused by the binding of aminoguanidine to the active site of AdoMetDC.