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Exonuclease III

recombinant, E. coli

Cat. No. Amount Price (EUR) Buy / Note
EN-157S 10000 units 55,00 Add to Basket/Quote Add to Notepad
EN-157L 5 x 10000 units 220,00 Add to Basket/Quote Add to Notepad

For in vitro use only!

Unit Definition: One unit of Exonuclease III catalyzes the release of 1 nmole of acid-soluble nucleotides from double stranded calf thymus DNA in 30 minutes at 37 °C in 33 mM Tris-acetate (pH 7.8), 66 mM K-acetate, 10 mM Mg-acetate and 0.5 mM DTT.

Shipping: shipped on blue ice

Storage Conditions: store at -20 °C
avoid freeze/thaw cycles

Shelf Life: 12 months

Accession number: M22592

Accession number: M22592

Purity: > 95 % (SDS-PAGE)

Form: liquid (Supplied in 50 mM Tris-HCl pH 7.5, 100 mM NaCl, 0.1 mM EDTA, 1 mM DTT, 0.1 % Triton X-100 and 50 % [v/v] glycerol)

Concentration: 200 units/μl


  • Construction of nested unidirectional deletions of DNA fragments in combination with nuclease S1
  • Generation of a single-stranded template for dideoxy sequencing of DNA
  • Site-directed mutagenesis
  • Cloning of PCR products
  • in vitro Rekombination

Exonuclease III (ExoIII) of E. coli is a 31 kD monomeric, globular protein combining multiple catalytic activities in one active site. It acts on double-stranded (ds) DNA as a 3'-5' exonuclease, a 3'-phosphomonoesterase, an apurinic/apyrimidimic (AP) sites specific endonuclease and an exonucleolytic ribonuclease H. Of particular interest for molecular biological methods is its exonucleolytic activity, removing 5'-mononucleotides from the 3'-hydroxyl ends of ds DNA, leaving protruding 5'-termini. Its catalytic rate can be adjusted by temperature and NaCl concentration and thus allows for the generation of single-stranded DNA templates for sequencing or recombination methods.

Selected References:
Henikoff (1984) Unidirectional digestion with exonuclease III creates targeted breakpoints for DNA sequencing. Gene 28:351.
Guo et al. (1082) New rapid methods for DNA sequencing based on exonuclease III digestion followed by repair synthesis. Nucleic Acids Res. 10:2065.
Vandeyar et al. (1988) A simple and rapid method for the selection of oligodeoxynucleotide-directed mutants. Gene 65:129.
Li et al. (1997) Ligation independent cloning irrespective of restriction site compatibility. Nucleic Acids Res. 25:4165.