5-formylcytosine

5-formylcytosine (5FC) is a rare base found in mammalian DNA. It participates in active DNA demethylation, changes DNA double helix structure, and reduces the transcription rate and substrate specificity of RNA polymerase II.

Recombinant Ten-Eleven Translocase is a recombinantly expressed dioxygenase that depends on Fe(II) and α-ketoglutarate. It catalyzes the conversion of 5-methylcytosine (5mC) into 5-hydroxymethylcytosine (5hmC), followed by further oxidation to 5-formylcytosine (5fC) and 5-carboxylcytosine (5caC). Subsequently, 5caC is converted into uracil (U) through chemical or enzymatic processes, and during PCR, uracil (U) is transformed into thymine (T), allowing for single-base resolution and highly accurate identification of DNA methylation sites.