Exonuclease VII has high enzymatic specificity for ssDNA and exhibits both 5´ to 3´ and 3´ to 5´ exonuclease activities. It is useful for rapid removal of single-stranded oligonucleotide primers from a completed PCR when different primers are required for subsequent PCR amplifications. Exonuclease VII digestion of ssDNA occurs in the absence of magnesium. Exonuclease VII can be inactivated by heating at 95°C for 10 minutes.
Unit Definition: One unit of Exonuclease VII catalyzes the release of 1 nmol of acid-soluble nucleotides from activated heat denatured 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 mM EDTA, 1 mM DTT, 0.1 M NaCl, and 0.1% Triton® X-100.
Quality Control: Exonuclease VII is tested for activity in degradation of ssDNA and is free of detectable RNase, endonuclease, and double-stranded exonuclease activities.