T5 Exonuclease is a product of T5 phage D15 gene derived from E. coli. T5 exonuclease degrades DNA in a 5’→3′ direction and also exhibits endonucleolytic activity on flap structures (branched duplex DNA containing a free single-stranded 5′-end). T5 exonuclease has been shown to have no effect on double stranded circular DNA.