Anti-CNP antibodies are used in the immunodetection of the protein 2',3'-cyclic nucleotide 3' phosphodiesterase. In humans, the canonical protein has a reported length of 421 amino acid residues and a mass of 47.6 kDa. Its subcellular localization is in the membrane. Up to 2 different isoforms have been reported for this protein. It is notably expressed in soft tissue, hippocampus, cerebral cortex, cerebellum, and caudate. A member of the CNPase protein family, CNP is known to catalyze the formation of 2'-nucleotide products from 2',3'-cyclic substrates (By similarity). CNP is also used as a cellular marker for characterizing oligodendrocytes. Synonyms for this target antigen include HLD20, 2', 3' cyclic nucleotide 3' phosphohydrolase, CNPase, and CNP1. CNP gene orthologs have been reported in the mouse, rat, bovine, frog, zebrafish, chimpanzee and chicken species.