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. Belongs to the 2H phosphoesterase superfamily. CNPase family. Sequencing errors.