The murine C-5 cytosine DNA methyltransferase (MTase, E.C.2.1.1.37) containing a hexahistidine affinity leader peptide has been expressed at levels which are at least 50-fold higher than previously reported. The recombinant enzyme has activity levels similar to the wild-type enzyme. The recombinant polypeptide binds to and elutes from a nickel affinity resin (IMAC resin). No dramatic differences in post-translational modification between the wild-type and recombinant enzyme were observed. The recombinant system will be useful in performing site-directed mutagenesis and will facilitate enzymological and biological investigations of this enzyme.