UDG enzyme (Uracil DNA Glycosylase) was found by American scientist Lindahl in Escherichia coli and Bacillus subtilis. The UDG enzyme and dUTP may be utilized to construct a PCR anti-pollution system that ensures accurate PCR amplification results. Almost all of PCR reagents used for clinical tests must have UDG enzyme technology to prevent contamination. Generally, two types of normal UDG enzymes developed from Escherichia coli and Bacillus subtilis and two types of heat-labile UDG enzymes generated from psychrophilic marine bacteria comprise the majority of commercially available UDG enzymes at present. UDG enzyme provided by Yeasen is an Escherichia coli-expressed and purified recombinant protein. It is active between 25 ℃ and 37 ℃, and 95 ℃ for 5-10 minutes causing irreversible inactivation.