A uracil-DNA glycosylase (UNG) from a psychro-PCR [10]. philic marine bacterium (BMTU 3346) has been purified to apparent homogeneity. The enzyme has a molecular weight of LING degrades contaminating uracil-containing DNA leav-23 400 Do. It is stable in complex buffers (containing glycerol/ ing the natural (thymine-containing) target DNA unaffected.
BSA), whereas it is heat-labile in dilute buffers (free ofFor this application usually the uracil-DNA glycosylase from stabilizers) with a half-life of 2 rain at 40°C. Due to the E. coli is used. However, it has been reported that the enzyme thermolability, uracil-DNA glycosylase is suitable for applieais not completely inactivated by heat denaturation, leading to tion in the carryover prevention technique showing less residual degradation of the PCR product affecting its integrity and activity and/or a slower reactivation rate than the usually applied yield. Furthermore, reactivation of UNG after PCR has UNG from Escheriehia coli.been discussed [12].In the present paper, the purification and characterization