Ornithine decarboxylase

![3D crystal structure of ornithine decarboxylase.[3]](/uploads/202501/31/Ornithine_Decarboxylase_Publication_View0518.png)
The enzyme ornithine decarboxylase (ODC) catalyzes the decarboxylation of ornithine (a product of the urea cycle) to form putrescine. This reaction is the committed step in polyamine synthesis. In humans, this protein has 461 amino acids and forms a homodimer.