ODCp is a 460 amino acid protein that is expressed in brain and testis. ODCp is a member of the Orn/Lys/Arg decarboxylase class-II family that catalyzes the creation of CO2 and agmatine from L-arginine. Mammalian ODCp differs from the forms expressed in bacteria and plants and shares less than 50% homology with Ornithine decarboxylase (ODC). ODCp is associated with the mitochondrial membrane where excess agmatine can be degraded by the enzyme Agmatinase or bound by the imidazoline recepto. In the brain, the highest levels of ODCp are found in the hypothalamus. Mammalian ODCp is thermally unstable and can be inhibited by Ca2+, Co2+ and polyamines.