Catalyzes the formation of 2'-nucleotide products from 2',3'-cyclic substrates (By similarity). May participate in RNA metabolism in the myelinating cell, CNP is the third most abundant protein in central nervous system myelin (By similarity). a nucleoside 2',3'-cyclic phosphate + H2O = a nucleoside 2'-phosphate + H(+) Exists as monomers and homodimers. Firmly bound to membrane structures of brain white matter. The disease may be caused by variants affecting the gene represented in this entry. Belongs to the 2H phosphoesterase superfamily. CNPase family.