T7 Endonuclease I

cat. no. E1125

T7 Endonuclease I is an ultrapure recombinant enzyme, the product of T7 gene 3, purified from E. coli. It is structure-selective enzyme that recognizes and cleaves mismatched DNA, heteroduplex DNA, cruciform DNA structures, Holliday structures or junctions and more slowly, nicked dsDNA. The cleavage site is the first, second or third phosphodiester bond that is 5’ to the mismatch. The enzyme has a preference for single stranded over double stranded DNA.


  • Recognition of mismatched DNA.
  • Resolve four-way junction or branched DNA.
  • Detect or cleave heteroduplex and nicked DNA.
  • Randomly cleave linear DNA for shot-gun cloning.