T5 Exonuclease is a nucleic acid exonuclease that degrades double- or single-stranded DNA in a 5' →3' direction. Degradation can begin either from the 5' end of double- or single-stranded DNA, or from gaps or nicks in linear or cyclic double-stranded DNA, but not from superhelix double-stranded DNA. T5 Exonuclease is often used for Gibson Assembly; Degradation of linear single-stranded, double-stranded DNA or absent plasmid DNA; Removal of incomplete ligation products from the linked cyclic double-stranded DNA; Degradation of linear and absent plasmid DNA to obtain high-purity supercoiled plasmid DNA; Removal of metamorphic DNA produced during plasmid extraction by alkali cleavage; Improve transfection efficiency of small extract plasmid cDNA libraries.