Promega, M1815, Exonuclease III

Exonuclease III catalyzes the stepwise removal of mononucleotides from dsDNA starting from a 3´-OH at nicks, blunt ends, recessed ends and 3´-overhangs of less than 4 bases, yielding nucleoside 5´-phosphates. This 3´→5´ exonuclease will also degrade DNA from 3´-phosphate ends due to its intrinsic 3´-phosphatase activity. In addition, the enzyme has apurinic endonuclease activity and ribonuclease H activity. The enzyme is used in conjunction with S1 nuclease for unidirectional deletion of sequences from the termini of DNA fragments. Exonuclease III is provided with a 10X Reaction Buffer consisting of 660mM Tris-HCl (pH 8.0 at 25°C), 6.6mM MgCl 2 .
References
Weiss, B. (1976) J. Biol. Chem. 251 , 1896–901.
Rogers, S.G. and Weiss, B. (1980) Meth. Enzymol. 65 , 201–11.
Henikoff, S. (1984) Gene 28 , 351–9.
Promega Product Information #9PIM181, Promega Corporation.
Storage Buffer: 20mM Tris-HCl (pH 7.5 at 25°C), 1mM DTT, 100mM KCl, 50% (v/v) glycerol.
Source: Recombinant E. coli strain.
QC Tests: Activity, SDS-PAGE/purity, endonuclease, 3´ overhang protection assay.
Unit Definition: One unit is defined as the amount of enzyme required to produce 1nmol of acid-soluble nucleotides from double-stranded DNA in 30 minutes at 37°C.
Applications
Generating nested sets of deletions with double-stranded, linear DNA.
Preparation of single-stranded DNA.