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This product includes both Exonuclease III enzyme and a 10X reaction buffer.
Key featuresShow Hide
- Produce stretches of ssDNA in dsDNA templates containing nicks, blunt ends or recessed 3' ends
- Protect protruding 3' ends because this exonuclease will not start digestion at protruding 3' overhangs
Size: 25000 units
Exonuclease III digests duplex DNA in a 3´ to ;5´ direction from a nick, a blunt end, or 3´-recessed end, producing stretches of ssDNA on the opposite strand. 5,6 Under defined reaction conditions, DNA degradation by Exonuclease III proceeds at a uniform rate yielding predictable and reproducible digestion results.
- Production of intermediates for site-directed mutagenesis. 1-3
- Production of strand-specific radiolabelled probes. 4
Because the rate of exonucleolytic excision of deoxyribonucleotides by Exonuclease III is dependent upon reaction factors including temperature, ionic strength, template sequence, and enzyme-to-DNA ratios, 4,7 each template must be optimised using sample digestions to achieve the desired excision rate.
Exonuclease III is not active on 3´-protruding ends of four bases or more in length, ssDNA, or on thioester-linked nucleotides. 2 The enzyme also has intrinsic RNase H, 3´-DNA phosphatase, and apurinic DNA endonuclease activities. 1,6
- Sambrook, J. et al. (1989) in: Molecular Cloning: A Laboratory Manual (2nd ed.), Cold Spring Harbor Laboratory Press, New York.
- Vandeyar, M.A. (1988) Gene 65, 129.
- Luckow, B. et al. (1987) Nucleic Acids Res. 15, 417.
- Richardson, C.C. et al. (1964) J. Biol. Chem. 239, 251.
- Weiss, B. (1976) J. Biol. Chem. 251, 1896.
- Rogers, S.G. and Weiss, B. (1980) Meth. Enzymol. 65, 201.
- Guo, L.H. and Wu, R. (1982) Nucleic Acids Res. 10, 2065.
Unit Definition: One unit of Exonuclease III catalyses the release of 1 nmol of acid-soluble nucleotides from double stranded calf thymus DNA in 30 minutes at 37 °C under standard assay conditions.
Storage Buffer: 50% glycerol containing 50 mM Tris-HCl (pH 7.5), 0.1 M NaCl, 0.1 mM EDTA, 1 mM DTT, and 0.1% Triton® X-100.
Exonuclease III 10X Reaction Buffer: 330 mM Tris-acetate (pH 7.5), 660 mM potassium acetate, 100 mM magnesium acetate, and 5 mM DTT.
Quality Control: Exonuclease III is free of detectable exogenous RNase, endonuclease, and single-stranded exonuclease activities.