Excises uracil residues from the DNA which can arise as a result of misincorporation of dUMP residues by DNA polymerase or due to deamination of cytosine. Not involved in strand-directed mismatch repair. Hydrolyzes single-stranded DNA or mismatched double-stranded DNA and polynucleotides, releasing free uracil. Optimum pH is 7.5-8. Induced in late G1 and early S phase of the cell cycle. Present with 4820 molecules/cell in log phase SD medium. Belongs to the uracil-DNA glycosylase (UDG) superfamily. UNG family.