Preparative Isolation of Purine Oligonucleotides from Partial Hydrolyzates of Depyrimidinated DNA

Abstract DNA is chemically degraded to a mixture of pure oligonucleotides. From the resulting partial hydrolyzate, defined oligonucleotides with two to six monomer units and defined mixtures of sequence-isomeric purine oligonucleotides are isolated in preparative amounts. The partial hydrolyzate is fractionated by a chromatographic separation route which uses anion-exchange chromatography on DEAE- and QAE-Sephadex at different pH values, paper chromatography, and reversed-phase HPLC. The sequence of the isolated oligonucleotides and the composition of the mixtures of sequence-isomers were determined from chromatographic data, absorption characteristics, enzymatic degradation, and “fingerprints.”