Dnmt1 methylates cytosine residues in hemimethylated DNA at 5’…CG…3′. Mammalian Dnmt1 is believed to be involved in carcinogenesis, embryonic development and several other biological functions. The b4k of the methylation takes place during DNA replication in the S-phase of the cell.
View Human DNA (cytosine-5) Methyltransferase on New England Biolabs’s website- Human DNA (cytosine-5) Methyltransferase