Figure 1.

Folate, one-carbon metabolism, methionine cycle and polyamine biosynthesis overview. Dietary folate (left) is necessary for de novo synthesis of deoxythymidine monophosphate (dTMP) and adenosylmethionine (AdoMet), which are necessary for DNA synthesis and intracellular methylation reactions, respectively. AdoMet is also used for polyamine (spermidine and spermine) biosynthesis (top). dTMP can also be scavenged by DNA degradation as thymidine, while AdoMet can be synthesized independently of folate by recycling methylthioadenosine (MTA) into methionine through the methionine salvage pathway.