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