Plasmid Substrates

All our DNA substrates are available separately and have been prepared to a high standard for accurate quantification of results. They are guaranteed for use with all our topoisomerase assay kits, buffers and enzymes.

Click on the product headings below to view details and order online.

Supercoiled pBR322 DNA

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Supercoiled plasmid pBR322 DNA is produced by the large-scale alkaline-lysis method ( Sambrook et al., 1989)1 from a high-copy derivative of pBR322 (Boros et al., 1984)2.

It is further treated so that the DNA is more supercoiled and has a narrow range of linking numbers making it an ideal substrate for relaxation reactions.

It is shipped on dry ice at a concentration of 1mg/ml in TE (10mM Tris-HCl (pH 7.5), 1mM EDTA). Store at 4oC

 

Technical Documents

Cat No. Product Price Quantity
S5001 Supercoiled pBR322 plasmid
50 µg
£110
S2502 Supercoiled pBR322 plasmid
250 µg
£405
S5003 Supercoiled pBR322 plasmid
500 µg
£784
S1004 Supercoiled pBR322 plasmid
1 mg
£1,505
POS5001 Positively Supercoiled pBR322 plasmid
50 µg
£210
POS2502 Positively Supercoiled pBR322 plasmid
250 µg
£892
Custom Quote

Relaxed pBR322 DNA

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Relaxed plasmid pBR322 DNA is produced by the large-scale alkaline-lysis method ( Sambrook et al., 1989)1 from a high-copy derivative of pBR322 (Boros et al., 1984)2 and the resulting supercoiled plasmid is relaxed using topoisomerase I. This is further purified and optimised for topoisomerase assays

It is shipped on dry ice at a concentration of 1mg/ml in TE (10mM Tris-HCl (pH 7.5), 1mM EDTA). Store at 4oC

0.5 µg of relaxed pBR322 when incubated with 1 U of DNA gyrase in a reaction volume of 30 µl at 37oC for 30 minutes in incubation buffer is completely converted to the supercoiled form.

Technical Documents

Cat No. Product Price Quantity
R5001 Relaxed pBR322 plasmid
50 µg
£110
R2502 Relaxed pBR322 plasmid
250 µg
£405
R5003 Relaxed pBR322 plasmid
500 µg
£784
R1004 Relaxed pBR322 plasmid
1 mg
£1,505
Custom Quote

Linear pBR322 DNA

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Linear plasmid pBR322 DNA is produced by the large-scale alkaline-lysis method ( Sambrook et al., 1989)1 from a high-copy derivative of pBR322 (Boros et al., 1984)2.

It is linearised by incubation with EcoRI and further concentrated and purified to a final concentration of of 1 mg/ml in TE (10 mM Tris-HCl (pH 7.5), 1 mM EDTA). Store at 4oC

It is shipped on dry ice. 

Technical Documents

Cat No. Product Price Quantity
L01050 Linear pBR322
150 µg
£95
L0300 Linear pBR322
300 µg
£168
L0600 Linear pBR322
600 µg
£336
L1000 Linear pBR322
1 mg µg
£525
Custom Quote

Linking Number Plasmid

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Plasmid pBR322 is partially negatively supercoiled to give specific linking numbers so that each marker has a range of 5-6 linking numbers. The kit contains a set of markers from relaxed plasmid covering approximately 23 linking numbers. Please enquire about single markers.

Technical Documents

Cat No. Product Price Quantity
LNM001 Linking Number markers
Set of 10 (20 µl of each at 1 µg/µl) enough for 10 gels
£220
Custom Quote

References

  1. Sambrook, J., Fritsch, E.F. & Maniatis, T (1989). Molecular cloning: a laboratory manual,2nd ed., Cold Spring Harbor Press. Cold Spring Harbor, NY.

  2. Boros, I., Pósfai, G. & Venetianer, P. (1984). High-copy number derivatives of the plasmid cloning vector pBR322. Gene 30, 257-260

  3. Trask, D. K. & Muller, M. T. (1983) Biochemical characterization of topoisomerase I purified from avian erythrocytes. Nucleic Acids Res. 11, 2779-2800

  4. Shapiro, T.A., Klein, V.A. and Englund, P.T. (1999) Isolation of kinetoplast DNA, in DNA Topoisomerase Protocols Vol.I (Bjornsti, M-A and Osheroff, N., eds.). Humana Press Inc., N. Jersey, pp. 61-68