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  • Protein Ladder (10-250 kDa)


    Protein Ladder is a mixture of 12 recombinant, highly purified proteins, which resolve into clearly identifiable sharp bands from 10-250 kDa when analyzed by SDS-PAGE and stained with Coomassie Brilliant Blue R-250 (1,2). This ladder is intended for use as a precise size standard when performing SDS-PAGE to calculate the molecular weight of a protein of interest. The 25 and 80 kDa bands have triple the intensity of the other proteins and serve as reference indicators. The molecular weights of the Protein Ladder are confirmed by sequencing, mass spectrometry and migration in a Laemmli SDS-Page Tris-Glycine system (3).



    Properties and Usage

    Storage Temperature


    Storage Conditions

    70 mM Tris-HCl
    33 mM NaCl
    40 mM DTT
    1 mM Na2EDTA
    10% Glycerol
    0.01% bromophenol blue
    2% SDS
    pH 6.8 @ 25°C


    1. For silver stained gels, dilute the Protein Ladder in 1:15 in buffer (70 mM Tris-HCl, pH 6.8, 33 mM NaCl, 1 mM Na2EDTA, 2% SDS, 40 mM DTT, 0.01% Bromophenol Blue and 10% glycerol).
    2. To ensure uniform mobility, load an equal volume of 1X Reducing SDS Loading Buffer into any unused wells.
    3. Approximate Protein Concentration: 0.1 mg/ml to 0.3 mg/ml.
    4. Recommended Load: 5 μl.


    1. Laemmli, U.K. (1970). Nature. 227, 680.
    2. Sambrook, J., Fritsch, E.F. and Maniatis, T. (2001). Molecular Cloning: A Laboratory Manual, (3nd ed.), Cold Spring Harbor: Cold Spring Harbor Laboratory Press.
    3. Ma, D. and Xu, MQ., New England Biolabs, Inc. unpublished results.

    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. Can I label the Protein Ladder with horseradish peroxidase (HRP) for western blotting?
    1. Using NEB Protein Markers & Ladders