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  • BG-NH2


    BG-NH2 is an amine-terminated building block for the one-step synthesis of SNAP-tag substrates from NHS esters or other activated carboxyl esters of labels or surfaces. This compound allows you to make custom SNAP-tag substrates for labeling SNAP-tag fusion proteins for a wide range of applications. The BG-NH2 is particularly useful for the synthesis of fluorescent SNAP-tag substrates. 

    The SNAP-tag protein labeling system enables the specific, covalent attachment of virtually any molecule to a protein of interest. The SNAP-tag is a protein based on human O6-alkylguanine-DNA-alkyltransferase (hAGT). SNAP-tag substrates are fluorophores, biotin or beads conjugated to guanine or chloropyrimidine leaving groups via a benzyl linker. In the labeling reaction, the substituted benzyl group of the substrate is covalently attached to the SNAP-tag.

    There are two steps to using this system: subcloning and expression of the protein of interest as a SNAP-tag fusion, and labeling of the fusion with the SNAP-tag substrate of choice. Expression of SNAP-tag fusion proteins is described in the documentation supplied with SNAP-tag plasmids. The labeling of fusion proteins with the SNAP-tag substrate is described in this document.

    Figure 1. Structure of BG-NH2 (MW 270.3 g/mol)

    Properties and Usage

    Storage Temperature


    Quality Control

    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.
    • Physical Purity (HPLC):
      The purity of the product is determined by HPLC analysis.


    1. Dry BG-NH2 should be stored at -20°C.
    2. BG-NH2 should be dissolved in anhydrous N,N-dimethylformamide (DMF) for use. BG-NH2 is sparingly soluble in anhydrous DMF. Heating at 37°C, vortexing and/or sonication will aid dissolution. Some remaining precipitate is expected and should be carried forward to the reaction. Remaining solids will continue to dissolve as the coupling reaction proceeds. Choose a solvent volume that will be compatible with the final use. Unused BG-NH2 substrate dissolved in DMF should be stored at -20°C.


    1. Keppler A. et al. (2004). Methods. 32, 437-444.
    2. Keppler A. et al. (2003). Nature Biotechnology. 21, 86-89.

    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. Cellular Imaging and Analysis FAQs
    1. Reaction Conditions for Chemical Coupling (S9148)
    2. Labeling SNAP-tag Fusion Proteins with BG-substrates (S9148)

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