Uracil-DNA-glycosylase (UDG) along with dUTP are used as part of PCR reagent to digest contaminating products before a new PCR reaction starts.
E. coli Uracil-DNA Glycosylase (UDG) catalyses the release of free uracil from uracil-containing DNA. UDG efficiently hydrolyzes uracil from single-stranded or double-stranded DNA, but not from oligomers (6 or fewer bases).