CNPase

2',3'-cyclic-nucleotide phosphodiesterase (CNPase) is a myelin-associated enzyme of the central nervous system. It is encoded by the CNP gene and is highly expressed in oligodendrocytes, with abundant localization to the myelin sheath. In most mammals, CNPase is a prominent component of CNS white matter and is less abundant in peripheral glia such as Schwann cells.

Enzymatic activity centers on hydrolyzing 2',3'-cyclic nucleotides to 2'-nucleotides, a reaction linked to RNA metabolism and possibly to myelin lipid turnover. The precise physiological function of CNPase remains a topic of study, but the enzyme is routinely used as a molecular marker for oligodendrocyte lineage and mature myelin in histology and research.

Genetic and experimental studies in mice show that loss of CNPase leads to hypomyelination and late-onset axonal degeneration, indicating a role in maintaining myelin integrity rather than initiating myelination. The enzyme exists in multiple isoforms generated by the CNP gene, and may be differentially expressed during oligodendrocyte differentiation.

Clinical and research relevance: CNPase levels and distribution can be altered in demyelinating diseases. Immunohistochemical detection of CNPase is used to identify oligodendrocytes and assess myelin status, though it is not a disease-specific diagnostic marker.