hydrolase activity DNA demethylase activity cytosine C-5 DNA demethylase activity GO:0051747 DNA demethylase activity hydrolytic DNA demethylase activity Catalysis of the reaction: methyl-dCpdG DNA + H2O = dCpdG DNA + methanol. This reaction is the hydrolytic removal of the methyl group on the 5 position of cytosine in DNA. DNA methyltransferase activity acting on cytosine C-5 molecular_function