Exonuclease III

Exonuclease III is a 3' to 5' exonuclease that removes mononucleotides from the 3'-hydroxyl termini of double-stranded DNA or DNA-RNA hybrids. Because a set number of mononucleotides are generated during each degradation, double-stranded DNA degradation is progressive. Exonuclease III will degrade double-stranded DNA containing a blunt end, a 5'-overhang, or a nick, but it will not degrade DNA with a 3'-overhang containing four or more bases. This 3' to 5' exonuclease can be inactivated by heating it at 65°C for 5 min. Exonuclease III is supplied in a buffer of 25 mM Tris-HCl (pH 8.0), 50 mM KCl, 0.5 mM DTT, and 50% glycerol.

More Information

Applications

  • Preparation of single-stranded DNA for dideoxy sequencing
  • Production of nested deletions in double-stranded DNA
  • DNA-protein interaction analysis 
  • Site-directed mutagenesis

Buffer

Supplied with 10X Reaction Buffer [500 mM Tris-HCl (pH 8.0), 50 mM MgCl2, 100 mM DTT]

Product citations

Guo, L.H. & Wu, R. [4] Exonuclease III: Use for DNA sequence analysis and in specific deletions of nucleotides. Methods Enzymol. 100, 60–96 (1983).

Wu, C. An exonuclease protection assay reveals heat-shock element and TATA box DNA-binding proteins in crude nuclear extracts. Nature 317, 84–87 (1985).

Additional product information

Please see the product's Certificate of Analysis for information about storage conditions, product components, and technical specifications. Please see the Kit Components List to determine kit components. Certificates of Analysis and Kit Components Lists are located under the Documents tab.