Separation of naturally occurring or induced methylated nucleobases of DNA by reversed-phase high-performance liquid chromatography.

Separation of the major bases of DNA along with seven minor methylated ones was obtained by reversed-phase high-performance liquid chromatography using an isocratic elution system. Application of this procedure to DNA treated in vitro by N-methyl-N-nitrosourea has allowed identification of two induced minor bases; a third one was resolved using a slightly modified mobile phase. Baseline resolution of 3-methyl- and 5-methylcytosine, detected in Euglena DNA hydrolyzates, was also achieved.