Exonuclease III, E. coli

Catalog No. 1140

Availability: In stock

Price From: $50.00

Quick Overview

A 3'→5' exonuclease releasing 5'-mononucleotides from the 3'-ends of DNA strands

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Price From: $50.00



Escherichia coli

Reagents Supplied

10X Exonuclease III Reaction Buffer


  • The 3'→5' exonuclease specific towards double-stranded DNA
  • Contains DNA 3'-phosphatase, hydrolyzing 3'-terminal phosphomonoesters
  • Contains AP endonuclease, cleaving phosphodiester bonds at apurinic or apyrimidinic sites to produce 5'-termini that are base-free deoxyribose 5'-phosphate residues (1)
  • Has ribonuclease H activity, preferentially degrading the RNA strand in a DNA-RNA hybrid duplex, presumably exonucleolytically (1)
  • Digests duplex DNA at nicks producing single-stranded gaps
  • Will not degrade double-stranded DNA with 3' overhang of at least 4 base pairs, single-stranded DNA or phosphorothioate-linked nucleotides
  • Ultrapure recombinant enzyme


  • For construction of nested unidirectional deletions of DNA fragments (2)
  • For generation of a single-stranded template for dideoxy-sequencing of DNA (3)
  • For site-directed mutagenesis (4) and cloning of PCR products (5)

Unit Definition

One unit is defined as the amount of enzyme required to produce 1 nmol of acid-soluble radio-activity in 30 minutes at 37°C (6).

Storage Buffer

25 mM Tris-HCl (pH 8.0)
0.05 mM dithiothreitol
50% glycerol 

Assay Conditions

See Certificate of Analysis Below.


Approximately ≥90% pure, as judged by SDS-polyacrylamide gel electrophoresis

Storage Conditions

Store at -20°C
Product shipped on dry ice


Certificate of Analysis
Lot 2011002 PDF 



(1) Rogers, S.G. and Weiss, B., Exonuclease III of Escherichia coli K-12, and AP endonuclease, Methods Enzymol., 65, 201-211, 1980
(2) Henikoff, S., Unidirectional digestion with exonuclease III creates targeted breakpoints for DNA sequencing, Gene 28, 351-359, 1984
(3) Guo, Li-He., Wu, R., New rapid methods for DNA sequencing based on exonulease II digesting followed by repair synthesis, Nucleic Acids Res. 10, 2065-2084, 1982
(4) Vandeyar, M.A. et al., A simple and rapid method for the selection of oligodeoxynucleotide-directed mutants, Gene 65, 129-133, 1988
(5) Li, C., Evans, R.M., Ligation independent cloning irrespective or restriction site compatibility, Nucleic Acids Res. 25, 4165-4166, 1997
(6) Richardson, C.C., Lehman, I.R. and Kornberg, A., J. Biol. Chem. 239, 251-258, 1964