Application Hero Banner

Pulse Chase

Pulse-chase experiments use labeled compounds to follow the dynamics of cellular processes and pathways. Molecules in a cell are continually being synthesized and degraded at various rates. Changes in molecule localizations and expression levels over time, can be detected by first “pulsing” or exposing cells to a labeled compound, then sequentially exposing the cells to the same compound, unlabeled, which is the “chase”. Compounds are commonly labeled with radioisotopes or fluorescent dyes. Turnover can be detected visually by microscopy techniques.

Various protein labeling methods for pulse-chase have specific application potentials. Reporter fluorescence fusion proteins are often used, but they can disrupt the native target protein's complexing behavior, be toxic to the cells, or affect target stability for pulse chase experiments. Fluorescence reporter fusion proteins also cannot be quenched. SNAP-tag® and CLIP-tag™ are useful for multicolor pulse-chase experiments. Sequential labeling with two or more fluorophores is possible. The non-overlapping substrate specificity of SNAP-tag and CLIP-tag permit simultaneous pulse-chase experiments to visualize different generations of two different proteins in one cell, further increasing the potential of the approach (1). Unlike with reporter fluorescence fusion proteins, like GFP, labeling of newly synthesized proteins can also be turned off using available blocking reagents (e.g., SNAP-Cell® Block). For development of pulse-chase techniques in thick tissues or animals (2), TIME-stamp tagging has advantages. Scalable proteomic analysis, detected by mass spectrometry, has been developed using a azidohomoalanine (azhal) label for rapid pulse-chase (3).

SNAP-tag® and SNAP-Cell® are registered trademarks of New England Biolabs, Inc.
CLIP-tag™ is a trademark of New England Biolabs, Inc.


  1. Gautier, A., Juillerat, A., Heinis, C. et al. (2008) Chem. Biol. 15, 128. PMID: 18291317
  2. Lin, M.Z. And Tsien, R.Y. (2010) Curr Protoc Protein Sci. Chapter 26, Unit 26.5. PMID: 20155731
  3. Kramer, G. Kasper, P.T., de Jong L, de Koster CG (2011) Methods Mol Biol. 753, 169-81. PMID: 21604123

Choose Type:

FAQs for Pulse Chase
Protocols for Pulse Chase
Application Notes for Pulse Chase
Features of SNAP-tag/CLIP-tag
  • 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
Applications of SNAP-tag/CLIP-tag
  • 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.
Legal Information

Products and content are covered by one or more patents, trademarks and/or copyrights owned or controlled by New England Biolabs, Inc (NEB). The use of trademark symbols does not necessarily indicate that the name is trademarked in the country where it is being read; it indicates where the content was originally developed. The use of this product may require the buyer to obtain additional third-party intellectual property rights for certain applications. For more information, please email

This product is intended for research purposes only. This product is not intended to be used for therapeutic or diagnostic purposes in humans or animals.