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ACP-tag and MCP-tag

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ACP-tag and MCP-tag are small protein tags based on the acyl carrier protein. In contrast to SNAP-tag and CLIP-tag, which are self-labeling, the presence of an added synthase is required for the formation of a covalent link between the ACP-tag or MCP-tag and their substrates, which are derivatives of Coenzyme A. In the labeling reaction, the group conjugated to CoA is covalently attached to the ACP-tag or MCP-tag by a recombinant synthase. Labels can be covalently attached to a tag using either ACP-Synthase (NEB #P9301) for ACP-tag labeling or SFP-Synthase (NEB #P9302) for dual ACP- and MCP-tag labeling.

ACP-tag or MCP-tag (red) fused to the protein of interest (blue) is labeled in the presence of a required synthase.


  • Small - Expressed tag is only 8 kDa (77aa)
  • Versatile - ACP- and MCP-tagged fusions can be co-expressed and sequentially labeled for two color applications on cell surfaces
  • Specific - Components remain exclusively extracellular, preventing intracellular labeling
  • Precise - Label is covalently bound under biological conditions in a defined position
  • Non-toxic - Substrates are non-toxic to living cells
  • Selection - Choice of substrates available, including 488, 547, 647 and biotin