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  • Human DNA (cytosine-5) Methyltransferase (Dnmt1)


    Dnmt1 methylates cytosine residues in hemimethylated DNA at 5'...CG...3' (1,2). Mammalian Dnmt1 is believed to be involved in carcinogenesis, embryonic development and several other biological functions (3-5). The bulk of the methylation takes place during DNA replication in the S-phase of the cell cycle (6).

    Product Source

    Dnmt1 is expressed from human Dnmt1 cDNA using a baculovirus expression system (1,7).

    Reagents Supplied

    The following reagents are supplied with this product:

    Store at (°C)Concentration
    Dnmt1 Reaction Buffer10X
    BSA-2010 mg/ml
    S-adenosylmethionine (SAM)-2032 mM

    Properties and Usage

    Unit Definition

    One unit is the amount of enzyme required to catalyze the transfer of 1 pmol of methyl group to poly dI.dC substrate in a total reaction volume of 25 μl in 30 minutes at 37°C.

    Reaction Conditions

    1X Dnmt1 Reaction Buffer
    Incubate at 37°C

    Usage Concentration

    2,000 units/ml

    Storage Temperature


    Storage Conditions

    50 mM Tris-HCl
    200 mM NaCl
    1 mM DTT
    1 mM EDTA
    50% Glycerol
    pH 7.5 @ 25°C

    Heat Inactivation

    65°C for 20 min

    Quality Control

    Quality Assurance Statement

    • Purified free of contaminating endonucleases and exonucleases.


    1. For DNA modification and protection applications, M.SssI (NEB #M0226) is preferred because it efficiently methylates both unmethylated and hemimethylated DNA substrates.


    1. Pradhan, S. et al. (1999). J. Biol. Chem. . 274, 33002-33010.
    2. Bacolla, A. et al. (1999). J. Biol. Chem. . 274, 33011-33019.
    3. Schmutte, C. et al. (1998). Biol. Chem. . 379, 377-388.
    4. Laird, P.W. et al. (1995). Cell. 81, 197-205.
    5. Li, E. et al. (1992). Cell. 12, 915-926.
    6. Leonhardt, H. et al. (1992). Cell. 71, 865-873.
    7. Yen, R.W. et al. (1992). Nucl. Acids. Res. . 20, 2287-2291.

    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. Is S-adenosylmethionine (SAM) supplied with the Methyltransferase?
    2. What source of tritiated SAM is recommended for use with Dnmt1?
    3. What should be considered if the methylation using Dnmt1 is not going to completion?
    4. How does Dnmt1 differ from SssI methylase?
    5. What is the specific activity of Dnmt1?
    6. Can Dnmt1 be heat inactivated?
    7. What is the protein concentration of dnmt1?