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    BC-GLA-NHS is an amine-reactive building block for the one-step synthesis of CLIP-tag™ substrates from amine-containing precursors including proteins, peptides or oligonucleotides. This building block allows you to make custom CLIP-tag substrates for labeling CLIP-tag fusion proteins.

    The CLIP-tag protein labeling system enables the specific, covalent attachment of virtually any molecule to a protein of interest. CLIP-tag is a protein tag based on human O6-alkylguanine-DNA-alkyltransferase (hAGT). CLIP-tag substrates are derivatives of benzylcytosine (BC). In the labeling reaction, the substituted benzyl group of the substrate is covalently attached to the reactive cysteine of CLIP-tag forming a stable thioether link. Although CLIP-tag is based on the same protein as SNAP-tag®, the benzylcytosine substrates form a separate class of substrates, different from the benzylguanine substrates recognized by SNAP-tag. CLIP-tag and SNAP-tag can be used for orthogonal and complementary labeling of two proteins simultaneously in the same cells.

    There are two steps to using this system: subcloning and expression of the protein of interest as a CLIP-tag fusion, and labeling of the fusion with the CLIP-tag substrate of choice. Expression of CLIP-tag fusion proteins is described in the documentation supplied with CLIP-tag plasmids. The labeling of the fusion proteins with the CLIP-tag substrate is described in this document.
    Figure 1. Structure of BC-GLA-NHS (MW 441.4 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. BC-GLA-NHS is supplied in lyophilized form and packaged under argon. The dry CLIP-tag building block substrate should be stored at -20°C.
    2. BC-GLA-NHS is soluble in anhydrous DMF or DMSO. Choose a solvent volume that will be compatible with the final use. Vortex and centrifuge briefly to remove any non-dissolved solids.
    3. NHS esters readily hydrolyze in moist environments. Experiments should be designed to maximize the usage of BC-GLA-NHS. Storage of unused BC-GLA-NHS solubilized in DMF or DMSO should be avoided. If unavoidable, we recommend storing at -20°C for the minimum time period.


    1. Gauthier, A. et al. (2008). Chemistry & Biology. 5, 128-136.

    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 (S9237)
    2. Labeling CLIP-tag Fusion Proteins with BC-substrates (S9237)

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