T7 DNA Polymerase

For a messophilic, highly processive, replicative DNA Polymerase

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T7 DNA Polymerase (3500 U)

Cat. No. / ID: P7260L

3500 U (evaluation pack) T7 DNA Polymerase (0.35 mL at 10,000 U/mL) and 10x T7 DNA Polymerase Buffer (1 x 1.5 mL)
The T7 DNA Polymerase (3500 U) is intended for molecular biology applications. This product is not intended for the diagnosis, prevention, or treatment of a disease.
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Features

  • OEM by QIAGEN offers customized bulk manufacturing of this enzyme.
  • Powerful 3' -> 5" nuclease activity that acts on both single and double stranded DNA

Product Details

T7 DNA Polymerase is a highly processive DNA polymerase with exceptionally high rate of synthesis and replication fidelity.

The enzyme is supplied in 50 mM KPO4, 0.1 mM EDTA, 1.0 mM DTT and 50% glycerol; pH 7.0 at 25°C.

10X T7 DNA Polymerase Buffer (B7260) contains the following: 400 mM Tris-HCl, 200 mM MgCl2 and 500 mM NaCl; pH 7.5 at 25°C.

Performance

T7 DNA Polymerase is the mesophilic, highly processive, replicative DNA polymerase from bacteriophage T7 that is responsible for the rapid and accurate replication of the virus’ genome during its infection cycle. T7 DNA Polymerase is a two subunit protein, consisting of a polymerase domain (gene 5 from the T7 bacteriophage) and a processivity factor (E. coli trxA gene thioredoxin) (1, 2). The enzyme possesses a powerful (3ʹ→5ʹ) nuclease activity that acts on both single and double stranded DNA and appears to be responsible for the high fidelity of this enzyme and prevents strand displacement synthesis (3, 4, 5). Enzyme not suitable for DNA sequencing.

Polymerase Properties

  • Storage temperature: –25°C to –15°C
  • Molecular weight: 92,140 Daltons
Test Specification
SDS Purity >99%
Specific activity 13,333 U/mg
Single-stranded exonuclease Functional
Double-stranded exonuclease Functional
Double-stranded endonuclease 100 U, no conversion
E. coli DNA contamination 100 U, <10 copies

References
1. Grippo, P., et al. (1971) J. Biol. Chem. 246:6867.
2. Modrich, P., et al. (1975) J. Biol. Chem. 250:5515.
3. Adler, S., et al. (1979) J. Biol. Chem. 254:11605.
4. Hori, K., et al. (1979) J. Biol. Chem. 254:11598.
5. Lechner, R.L.. et al. (1983) J. Biol. Chem. 258:11185.

Principle

Source of recombinant enzyme protein
The protein is produced by a recombinant E. coli strain carrying the bacteriophage T7 gene 5.

Unit definition
One unit is defined as the amount of polymerase required to convert 10 nmol of total dNTPs into acid insoluble material in 30 minutes at 37°C.

 

Procedure

Instructions

The following workflow can be applied to either second-strand synthesis following first-strand synthesis off an RNA template, or to a site-directed mutagenesis experiment where the mutagenic primer is extended such that the entire template strand is copied.

In a sterile reaction vessel, combine the following components:

Amount Description Final concentration
20 µL Pre-annealed primer/template 20 nmol complex
4 µL 10x T7 DNA Polymerase Buffer 1x
0.5 µL 25 mM dNTP Solution (cat. no. N2050L) 300 µM
2 µL T7 DNA Polymerase (cat. no. P7260L) 500 U/mL
2 µL T4 DNA Ligase (cat. no. L6030-LC-L) 2400 U/mL
10 µL Type I Water N/A
40µL Total volume  

Incubate 60 min at 37°C. Incubate 10 min at 70°C to stop the reaction.

Quality control analysis

Unit activity was measured using a twofold serial dilution method. Dilutions of enzyme were made in 1x reaction buffer and added to 50 µl reactions containing calf thymus DNA, 1x T7 DNA Polymerase Unit Cheracterization Buffer (20 mM Tris-HCl, 100 mM KCl, 6 mM MgCl2, 0.1 mM EDTA, 5 mM β-mercaptoethanol), 3H-dTTP and 150 µM dNTPs. Reactions were incubated 10 minutes at 37°C, placed on ice, and analyzed using the method of Sambrook and Russell (Molecular Cloning, v3, 2001, pp. A8.25-A8.26).

Protein concentration is determined by OD280 subscript absorbance.

Physical purity is evaluated by SDS-PAGE of concentrated and diluted enzyme solutions followed by silver-stain detection. Purity is assessed by comparing the aggregate mass of contaminant bands in the concentrated sample to the mass of the band corresponding to the protein of interest in the diluted sample.

Single-stranded exonuclease is determined in a 50 µl reaction containing a radiolabeled single-stranded DNA substrate and 10 µl of enzyme solution incubated for 4 hours at 37°C.

Double-stranded exonuclease activity is determined in a 50 µl reaction containing a radiolabeled double-stranded DNA substrate and 10 µl of enzyme solution incubated for 4 hours at 37°C.

Double-stranded endonuclease activity is determined in a 50 µl reaction containing 0.5 µg of plasmid DNA and 10 µl of enzyme solution incubated for 4 hours at 37°C.

E. coli contamination is evaluated using 5 µl replicate samples of enzyme solution that are denatured and screened in a TaqMan qPCR assay for the presence of contaminating E. coli genomic DNA using oligonucleotide primers corresponding to the 16S rRNA locus.

Applications

This OEM by QIAGEN product is available for bulk purchase for the following commercial assay applications.

  • Useful for copying long stretches

Resources

Safety Data Sheets (1)