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.
Applications
Preparation of single-stranded DNA for dideoxy sequencing
Production of nested deletions in double-stranded DNA
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).
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.
Applications
Preparation of single-stranded DNA for dideoxy sequencing
Production of nested deletions in double-stranded DNA
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).
