Polyamines are vital for the growth and function of normal cells. The complexity of polyamine metabolism and the multitude of compensatory mechanisms that are invoked to maintain polyamine homoeostasis argue that these amines are critical to cell survival. The regulation of polyamine content within cells occurs at several levels, including transcription and translation (Ref.1). The amino-acid derived polyamines like Putrescine, Spermidine and Spermine that are the main polyamines found in prokaryotes and eukaryotes, have long been associated with cell growth and cancer, and specific oncogenes and tumor suppressor genes regulate polyamine metabolism. Regulation of these polyamines (otherwise known as “organic cations”) is chiefly associated with cancers pertaining to the colon. They are formed by the enzymatic decarboxylation of the amino acids like Ornithine or Arginine by ODC1 (Ornithine Decarboxylase-1) the enzyme required for the first stage in polyamine synthesis. ODC1 is subject to both positive and negative feedback regulation by polyamines: high polyamine concentrations decrease, and low polyamine concentrations increase, activity (Ref.2 & 3).
References:
1.A perspective of polyamine metabolism.
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