Abstract
Cyclic nucleotides (2[image],3[image]-monohydrogenphosphate esters of nucleosides) were obtained from ribonucleic acids with ribonuclease and with careful alkaline hydrolysis. The separation of these substances by paper strip electrophoresis is described. U.v. absorption and electrophoretic mobility are described. The cyclic pyrimidine nucleotides are digested by ribonuclease to ordinary nucleotides; the analogous purine derivatives are not.