Cellular Analysis
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  • SNAP Companion

    The non-overlapping substrate specificity of SNAP-tag® and CLIP-tag™ enables the orthogonal and complementary labeling of two proteins simultaneously in the same cell. Furthermore, SNAP-tag and CLIP-tag based pulse-chase experiments allow for visualization of different generations of proteins and analysis of protein turnover in living cells (1-3). Additionally, there are a numbers of companion products designed to enable a wide variety of other applications including: Biotin substrates, SDS-PAGE specific SNAP-tag and CLIP-Vista labels, non-fluorescent blocking agents, resin and magnetic beads for pull-down applications, building blocks for the generation of custom substrates, and a SNAP-tag specific purified protein and antibody.


    1. Jansen, L. et al (2007) J.Cell. Biol. 176, 795-805. PMID: 17339380
    2. Farr, G.A. (2009) J. Cell. Biol. 186, 269-282. PMID: 19620635
    3. Milenkovic, L. (2010) J. Cell. Biol. 187, 365-374. PMID: 19948480

    SNAP-tag® is a registered trademark of New England Biolabs, Inc.
    CLIP-tag™ is a trademark of New England Biolabs, inc.

    • Fluorescent Labeling of COS-7 Expressing SNAP-tag® Fusion Proteins for Live Cell Imaging

      Watch as Chris Provost, of New England Biolabs, performs fluorescent imaging of live COS-7 cells expressing SNAP-tag® fusion proteins.

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    • SNAP-tag® Overview Tutorial

      View an interactive tutorial explaining the mechanism of our SNAP-tag® technologies and reagents available for researchers wishing to study the function and localization of proteins in live or fixed cells.

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    Featured Products

    FAQs for SNAP Companion


    • Clone and express once, then use with a variety of substrates
    • Non-toxic to living cells
    • Wide selection of fluorescent substrates
    • Highly specific covalent labeling
    • Simultaneous dual labeling


    • Simultaneous dual protein labeling inside live cells
    • Protein localization and translocation
    • Pulse-chase experiments
    • Receptor internalization studies
    • Selective cell surface labeling
    • Protein pull-down assays
    • Protein detection in SDS-PAGE
    • Flow cytometry
    • High throughput binding assays in microtiter plates
    • Biosensor interaction experiments
    • FRET-based binding assays
    • Single molecule labeling
    • Super-resolution microscopy

    Protein labeling with SNAP-tag and CLIP-tag

    The SNAP- (gold) or CLIP-tag (purple) is fused to the protein of interest (blue). Labeling occurs through covalent attachment to the tag, releasing either a guanine or a cytosine moiety.

    SNAP-tag®, CLIP-tag™ and ACP/MCP-tag Substrate Selection Chart

    NEB offers a large selection of fluorescent labels (substrates) for SNAP-, CLIP-, ACP- and MCP-tag fusion proteins.