Uracyl-DNA-glycosylase (UDG) is a single polypeptide with the molecular weight 26 kDa. Uracyl-DNA-glycosylase catalyzes the release of the free uracyl from uracyl-containing DNA. UDG effectively hydrolyzes the uracyl from one and two-chain DNA, but not from oligomers (with 6 or fewer bases).
It is used in combination with Hot-start Taq polymerase for lowering the contamination level of the PCR reaction with amplicons. The ferment is inactivated at the temperature over 40 °C.