Quality Assurance Statement:
ET RecA is purified free of contaminating endonucleases and exonucleases. Each lot is tested for single-stranded DNA-dependent ATPase activity and is visually determined to be > 95% pure on an SDS-polyacrylamide gel.
Exonuclease Activity:
Incubation of 20 µg ET RecA for 4 hours at 37°C in 50 µl reaction buffer containing 50 mM potassium acetate, 20 mM Tris-acetate, 10 mM magnesium acetate and 1 mM dithiothreitol, pH 7.9 @ 25°C, with 1 µg of a mixture of single and double-stranded [3H] E. coli DNA (200,000 cpm/µg) released < 0.05% of the total radioactivity.
Endonuclease Assay:
Incubation of 10 µg ET RecA for 4 hours at 37°C in 50 µl reaction buffer containing 50 mM potassium acetate, 20 mM Tris-acetate, 10 mM magnesium acetate and 1 mM dithiothreitol, pH 7.9 @ 25°C, with 1 µg ΦX174 RF I DNA gave < 5% conversion to RF II.
Nuclease Activity:
Incubation of 20 µg ET RecA for 16 hours at 37°C in 50 µl of reaction buffer containing 50 mM potassium acetate, 20 mM Tris-acetate, 10 mM magnesium acetate and 1 mM dithiothreitol, pH 7.9 @ 25°C, with 1 µg λ DNA yielded a clear and sharp band on an agarose gel.
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