Fig. 2.

Structure of azanucleosides. Structure of deoxycitidine and the two azanucleosides azacitidine (AZA) and decitabine (DAC). DAC is the 2′didesoxy form of AZA, incorporated into DNA upon triphosphorylation. AZA is primarily incorporated into RNA. Upon triphosphorylation and reduction by the enzyme ribonucleotide reductase it is also incorporated into DNA. The red circles highlight structural differences between deoxycytidine and the two azanucleosides AZA and DAC. The purple circle highlights the structural difference between AZA and DAC