Adenine Methylation Analysis with DpnI
Dpn I is a Type IIM restriction enzyme that specifically cleaves DNA containing methylated adenine (mA) in the recognition sequence GmA | TC, also referred to as the dam sequence since it is recognized by Dam methylase. Dpn I does not cleave unmethylated DNA, and will cleave hemimethylated DNA (with only one adenine methylated) 60-fold more slowly than fully adenomethylated recognition sequences. While DpnI shares the same recognition sequence as DpnII, Sau3AI, and MboI, the isoschizomers have different methylation sensitivities. Sau3AI is insensitive to adenomethylation but will not cleave if one or more cytosines in the recognition sequence are methylated. DpnII and MboI do not cleave adenomethylated sequences.