The rapid purification of T4 DNA ligase from a lambda T4 lig lysogen.

A procedure has been developed for the rapid purification of the enzyme T4 DNA ligase. The procedure involves the induction at 42 degrees C of a lambda lysogen containing the gene for T4 DNA ligase (Murray, N.E., Bruce, S.A., and Murray, K. (1979) J. Mol. Biol. 132, 493-504), followed by purification of the ligase activity by phosphocellulose and hydroxylapatite chromatography. This results in the purification of large amounts of ligase with very high specific activity. The enzyme is free of contaminating exo- and endonuclease activities and active in the ligation of DNA fragments possessing cohesive or blunt-end termini.