Double-strand specific DNases

Double-strand specific DNases (dsDNases) are unique double-strand specific endonucleases. As they do not digest ssDNA or RNA, they can be used to specifically remove dsDNA in the presence of other nucleic acids. The enzymes are heat-labile, which makes them ideal for applications where the DNase have to be inactivated. There are two versions of this enzyme available, dsDNase and HL-dsDNase.

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Glycerol-free and Triton FREE versions of

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dsDNase and HL-dsDNase are now available

Properties

Specificity towards double-stranded DNA
Nucleic acid specificity has been tested towards double- and single-stranded DNA and RNA oligonucleotides.

The specificity of dsDNase towards the substrate has been measured using 15-mer oligonucleotides with FAM at 5′ and DarkQuencher® 3′ (Eurogentec). The fluorescence is proportional to enzyme activity.

Assay conditions: 25 mM Tris pH 7.5, 5 mM MgCl2, and 2 μM oligonucleotide.

Relative activities
Substrate Relative activity
dsDNA 100%
ssDNA < 0.03%
dsRNA < 0.01 %
ssRNA < 0.01 %

From the data above we can conclude that the dsDNase is double-strand specific.

dsDNase

Heat inactivation
The dsDNase can be heat inactivated by heat treatment at 15 min at 65˚C, or 20 min at 60˚C. The enzyme requires 1 mM DTT and pH ≥ 8 for complete inactivation.

Specifications

  • Unit definition
    One Unit is defined as an increase in absorbance at 260 nm of 0.001 per minute, using 50 µg/ml high MW DNA in 100 mM Na-acetate pH 5.0 and 5 mM MgCl2.
  • Specific activity
    Ca. 400 000 Kunitz Units/mg.
  • Activity
    The dsDNase is highly active in a temperature range of 20-40°C. It needs at least 2.5 mM Mg for activity and has an optimal pH at 7.5.
  • Storage buffer
    20 mM Tris-HCl pH 7.5, 2 mM MgCl2, 10 mM NaCl, 0.01% (v/v) Triton X-100, 50% (v/v) glycerol.
  • Purity
    dsDNase is purified to apparent homogeneity.
  • Storage
    Minimum shelf life is 3 years at -20°C. Storage at 4°C is possible for at least 6 months. The enzyme also tolerates multiple freeze-thaw cycles.

HL-dsDNase

Heat inactivation
The HL-dsDNase can be heat inactivated by heat treatment at 5 min at 58˚C. The enzyme requires 1 mM DTT and pH ≥ 8 for complete inactivation.

Specifications

  • Unit definition
    One unit is defined as an increase in absorbance at 260 nm of 0.001 per minute, using 50 µg/ml of high MW DNA in 100 mM Na-acetate pH 5.0 and 5 mM MgCl2.
  • Specific activity
    Ca. 200 000 Kunitz Units/mg.
  • Activity
    The HL-dsDNase is highly active in a temperature range of 20-40°C. It needs at least 2.5 mM Mg for activity and has an optimal pH at 7.5.
  • Storage buffer
    20 mM Tris-HCl pH 7.5, 2 mM MgCl2, 10 mM NaCl, 0.01% (v/v) Triton X-100, 50% (v/v) glycerol.
  • Purity
    HL-dsDNase is purified to apparent homogeneity.
  • Storage
    Minimum shelf life is 2 years at -20°C. The enzyme also tolerates multiple freeze-thaw cycles.