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  • T7 Exonuclease

    cloned at neb recombinant NEBuffer 4 incubation temp heat inactivation no
    Catalog #SizeConcentrationPriceQtyAdd to Cart
    M0263S1,000 units10,000 units/ml$60.00Add to Cart
    M0263L5,000 units10,000 units/ml$240.00Add to Cart
    Nuclease Products


    T7 Exonuclease acts in the 5' to 3' direction, catalyzing the removal of 5' mononucleotides from duplex DNA. T7 Exonuclease is able to initiate nucleotide removal from the 5' termini or at gaps and nicks of double-stranded DNA (1). It will degrade both 5' phosphorylated or 5' dephosphorylated DNA. It has also been reported to degrade RNA and DNA from RNA/DNA hybrids in the 5' to 3' direction but is unable to degrade either double-stranded or single-stranded RNA (2). The protein is the product of T7 gene 6.


    • Isolated from a recombinant source
    • 5' -> 3' exonuclease
    • Supplied with 10X Reaction Buffer

    Product Source

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

    Reagents Supplied

    The following reagents are supplied with this product:

    Store at (°C)Concentration
    NEBuffer 4-2010X

    Properties and Usage

    Unit Definition

    One unit is defined as the amount of enzyme required to produce 1 nmol of acid-soluble deoxyribonucleotide in a total reaction volume of 50 μl in 30 minutes at 37°C in 1X NEBuffer 4 with 0.15 mM sonicated duplex [3H]-DNA.

    Reaction Conditions

    1X NEBuffer 4
    Incubate at 25°C

    1X NEBuffer 4:
    50 mM Potassium Acetate
    20 mM Tris-acetate
    10 mM Magnesium Acetate
    1 mM DTT
    pH 7.9 @ 25°C

    Storage Temperature


    Storage Conditions

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

    Heat Inactivation


    Quality Control

    Quality Assurance Statement

    • Purified free of contaminating exonucleases and endonucleases.

    Quality Control Assays

    The following Quality Control Tests are performed on each new lot and meet the specifications designated for the product. Individual lot data can be found on the Product Summary Sheet/Datacard or Manual which can be found in the Supporting Documents section of this page.
    • Endonuclease Activity (Nicking):
      The product is tested in a reaction containing a supercoiled DNA substrate. After incubation for 4 hours the percent converted to the nicked form is determined by agarose gel electrophoresis.
    • Single-Stranded DNase Activity (Radioactivity Release):
      The product is tested in reaction containing radiolabeled single-stranded DNA. After incubation the exonuclease activity is determined by the % release of radioactive nucleotides.


    1. Kerr, C. and Sadowski, P.D. (1972). J. Biol. Chem. 247, 305-318.
    2. Shinozaki, K. and Okazaki, T. (1978). Nucl. Acids. Res. 5, 4245-4261.

    Supporting Documents

    Material Safety Datasheets

    The following is a list of Material Safety Data Sheets (MSDS) that apply to this product to help you use it safely. The following file naming structure is used to name these document files: [Product Name] MSDS. For international versions please contact us at info@neb.com.


    The Product Summary Sheet, or Data Card, includes details for how to use the product, as well as details of its formulation and quality controls. The following file naming structure is used to name the majority of these document files: [Catalog Number]Datasheet-Lot[Lot Number]. For those product lots not listed below, please contact NEB at info@neb.com or fill out the Technical Support Form for appropriate document.
    1. How Does T7 Exonuclease differ from Lambda Exonuclease (NEB# M0262)?
    2. How Does T7 Exonuclease differ from Exonuclease III (NEB# M0206)?
    3. What is the activity of T7 Exonuclease in the NEBuffers?
    4. Can T7 Exonuclease be heat inactivated?
    5. What is the best way to generate partials using T7 Exonuclease?
    6. Can DNA be blunted using T7 Exonuclease?

    Selection Tools

    Addition of 6 phosphorothioates to the 5’ end of DNA can block activity up to 90%.