DNA Substrates and Markers

All our DNA substrates are available separately and have been prepared to a high standard for accurate quantitation of results. They are guaranteed for use with all our assay kits 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 number 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 4°C.

Technical Documents

Cat No. Product Price Quantity
S5001 Supercoiled pBR322 plasmid
50 µg
£105
S2502 Supercoiled pBR322 plasmid
250 µg
£386
S5003 Supercoiled pBR322 plasmid
500 µg
£746
S1004 Supercoiled pBR322 plasmid
1 mg
£1,433
POS5001 Positively Supercoiled pBR322 plasmid
50 µg
£200
POS2502 Positively Supercoiled pBR322 plasmid
250 µg
£850
Custom Quote

Relaxed 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 number derivative of pBR322 (Boros et al.,1984)2 and is relaxed using chicken erythrocyte topoisomerase I (Trask and Muller, 1983)3.

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

0.5 µg of relaxed pBR322 when incubated with 1 U of DNA gyrase in a reaction volume of 30 µl at 37°C 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
£105
R2502 Relaxed pBR322 plasmid
250 µg
£386
R5003 Relaxed pBR322 plasmid
500 µg
£746
R1004 Relaxed pBR322 plasmid
1 mg
£1,433
Custom Quote

Linear 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 number 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 1.0 mg/ml in TE (10mM Tris-HCl (pH 7.5), 1mM EDTA). Store at 4°C.

Technical Documents

Cat No. Product Price Quantity
L0150 Linear pBR322
150 µg
£90
L0300 Linear pBR322
300 µg
£160
L0600 Linear pBR322
600 µg
£320
L1000 Linear pBR322
1 mg
£500
Custom Quote

kDNA (isolated from Crithidia fasciculata)

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Kinetoplast DNA (kDNA) is purified from Crithidia fasciculata using the method described in Shapiro (Shapiro et al., 1999)4 and is supplied at a concentration of 100 ng/µl in 10 mM Tris-HCl (pH8.0), 1 mM EDTA. kDNA is an excellent substrate for use in topo IV assays and results can be obtained more quickly than those from relaxation assays because the decatenated mini circles can easily be resolved from the non-decatenated material which remains in the wells of the gel. Store at 4°C.

Technical Documents

Cat No. Product Price Quantity
K2001 kDNA
20 µg
£105
K1002 kDNA
100 µg
£386
K2003 kDNA
200 µg
£596
K4004 kDNA
400 µg
£900
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 (20ul of each at 1ug/ul) enough for 10 gels
£210
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