Exonuclease III, E. coli

Source

Escherichia coli

Reagents Supplied

10X Exonuclease III Reaction Buffer

Description

• 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

Applications

• 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 

Purity

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

Storage Conditions

Store at -20°C
Product shipped on dry ice