Lysine 69 on ornithine decarboxylase (ODC) binds the cofactor pyridoxal phosphate to form a Schiff base.

Binding between monomers is relatively weak, and ODC interconverts rapidly between monomeric and dimeric forms in the cell.

Therefore, ornithine decarboxylase is an essential enzyme for cell growth, producing the polyamines necessary to stabilize newly synthesized DNA.

[15] Ultraviolet light,[16] asbestos[17] and androgens released by the prostate gland[18] are all known to induce increased ODC activity associated with cancer.

[15] Mutations of the ODC1 gene have been shown to cause Bachmann-Bupp syndrome (BABS), a rare neurometabolic disorder characterized by global developmental delay, alopecia, macrocephaly, dysmorphic features, and behavioral abnormalities.

[21] ODC gene expression is induced by a large number of biological stimuli including seizure activity in the brain.

[22] Inactivation of ODC by difluoromethylornithine (DMFO, eflornithine) is used to treat cancer and facial hair growth in postmenopausal females.

ODC is also an enzyme indispensable to parasites like Trypanosoma, Giardia, and Plasmodium, a fact exploited by the drug eflornithine.

[26] Recent studies have shown the importance of ODC and polyamine synthesis in T helper cell fate commitment.