Sequence-specific DNA affinity chromatography: application to the purification of EcoRI and SphI.

Several rapid and effective methods have been described to obtain restriction endonucleases suitable for commercial exploitation. However, lengthy and laborious protocols have been necessary to obtain homogeneous enzymes. We now report the use of sequence-specific DNA affinity chromatography to purify restriction endonucleases to near homogeneity. Restriction endonucleases EcoRI and SphI from the microorganisms Escherichia coli RY 13 and Streptomyces phaeochromogenes, respectively, were purified to near homogeneity employing a two-step procedure which involves DNA-cellulose chromatography and oligonucleotide-ligand affinity chromatography.