Figure 2.

The polyamine pathway in mammalian cells. Details of the pathway are described in the text. Metabolic enzymes are in green while enzymes of polyamine catabolism are in orange. Ornithine decarboxylase (ODC) inhibitors α-difluoromethylornithine (DFMO) and antizyme (AZ) are in blue. In addition to inhibiting ODC, AZ causes the ODC protein to be degraded and has the additional effect of inhibiting polyamine transport by an unknown mechanism. Other abbreviations are as follows: S-adenosylmethionine decarboxylase (AdoMetDC); S-adenosylmethionine (AdoMet); decarboxylated S-adenosylmethionine (dcAdoMet); Spermidine/spermine N¹-acetyltransferase (SSAT); N¹-acetylpolyamine oxidase (APAO); spermine oxidase (SMO).