T7 Exonuclease

Description:
T7 Exonuclease is similar to Lambda Exonuclease in that it catalyzes the stepwise hydrolysis of duplex DNA from the 5'-termini, liberating 5'-mononucleotides. However, unlike Lambda Exonuclease, the enzyme has low processivity and it will remove both 5'-hydroxyl and 5'-phosphoryl termini. T7 Exonuclease hydrolyzes duplex DNA non-processively in the 5' -> 3' direction from both 5'-phosphoryl or 5'-hydroxyl nucleotides by liberating oligonucleotides, as well as mononucleotides, until about 50% of the DNA is acid soluble.

Source:
Purified from an E. coli strain containing a TYB₁₂ intein fusion.

Storage Conditions
10 mM Tris-HCl
5 mM DTT
0.1 mM EDTA
50% Glycerol
pH 8.0 @ 25°C

Application:
- Controlled stepwise digestion of double-stranded DNA from the 5'-termini.
- Generating ssDNA templates for sequencing via the chain-termination method.

Supplied with:
10X T7 Exonuclease Buffer

10X T7 Exonuclease Buffer:
500 mM Potassium Acetate
200 mM Tris-acetate
100 mM Magnesium Acetate
10 mM DTT
pH 7.9 @ 25°C

Unit Definition:
One unit is the amount of enzyme required to release 1 nmol of acid soluble nucleotide in 15 min at 37°C under standard assay conditions.

Recommended Storage Condition: -20°C

References:
1. Kerr, C. and Sadowski, P. D. (1972) J. Biol. Chem. 247, 311-318.
2. Thomas, K. R. and Olivera, B. M. (1978) J. Biol. Chem. 253, 424-429.
3. Ausubel, F. M., Brent, R., Kingston, R. E., Moore, D. D., Seidman, J. G., Smith, J. A. and Struhl, K., (1987) Current Protocols in Molecular Biology (John Wiley and Sons, Inc.
4. Shon, M., Germino, J. and Bastia, D. (1982) J. Biol. Chem. 257, 13823-13827.
5. Nikiforov, T. T., Rendle, R. B., Goelet, P., Rogers, Y. H., Kotewicz,
6. M. L., Anderson, S., Trainor, G. L. and Knapp, M. R. (1994) Nucl. Acids Res 22, (20), 4167-4175.
7. Kornberg, A. and Baker, T. (1991) DNA Replication, Second Edition, 591.