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Human IgG4-Pro-FcSpyCatcher3

Human IgG4-Pro-FcSpyCatcher3

Product Type
Recombinant Protein
Human IgG4-Pro-FcSpyCatcher3

Product Code Applications Pack Size List Price Your Price Qty
Datasheet Datasheet Datasheet
SDS Safety Datasheet SDS
IY 0.5 mg loader
List Price Your Price

Human IgG4-Pro-FcSpyCatcher3 (hIgG4-Pro-FcSpyC3) contains a SpyCatcher3 (Keeble et al. 2019) fused to the hinge region, CH2 and CH3 of human IgG4-Pro (Hentrich et al. 2020), resulting in a 76.5 kDa protein for the disulfide-bridged dimer. The IgG4-Pro sequence has a mutation S228P in the core hinge region that prevents the formation of IgG4 half molecules. Each SpyCatcher3 subunit can form a stable covalent isopeptide bond with a second protein that includes a SpyTag. The reaction occurs spontaneously on mixing, is rapid, irreversible, high-yielding and shows good specificity. The reaction is robust at pH 5 to 8, at temperatures from +4°C to +37°C, in various buffer conditions (Ca2+/Mg2+ not needed) and in the presence of detergents. The reaction also occurs inside cells (in vivo). Since the speed of the coupling reaction is concentration dependent, it is recommended to use hIgG4-Pro-FcCatcher3 undiluted.

Human IgG4-Pro-FcSpyCatcher3 is compatible with Bio-Rad's recombinant HuCAL antibodies with a SpyTag2 at the C-terminus of the heavy chain.

Download FcSpyCatcher coupling protocol

View all available Catchers

Target Species
Protein/peptide tag
Product Form
Purified recombinant protein - Liquid
Recombinant protein expressed in mammalian cell line and purified by affinity chromatography
Buffer Solution
Phosphate buffered saline
Preservative Stabilisers
0.1% ProClin 950
≥90% determined by SDS-PAGE under reducing conditions and visualized by coomassie blue staining
Approx. Protein Concentrations
80 µM (6.1 mg/ml)
Protein Molecular Weight
Predicted 76514 Da
For research purposes only
12 months from date of despatch
ProClin is a trademark of The Dow Chemical Company (“Dow”) or an affiliated company of Dow
This product and/or its use is covered by claims of U.S. patents, and/or pending U.S. and non-U.S. patent applications owned by or under license to Bio-Rad Laboratories, Inc. See for details.
Licensed Use
For in vitro research purposes. Any re-sale in any form or any other commercial application needs a written agreement with Bio-Rad.

Store at -20°C only.
Storage in frost-free freezers is not recommended.
This product should be stored undiluted. Avoid repeated freezing and thawing as this may denature the protein. Should this product contain a precipitate we recommend microcentrifugation before use.

This product has been reported to work in the following applications. This information is derived from testing within our laboratories, peer-reviewed publications or personal communications from the originators. Please refer to references indicated for further information. For general protocol recommendations, please visit the antibody protocols page.
Application Name Verified Min Dilution Max Dilution
Where this product has not been tested for use in a particular technique this does not necessarily exclude its use in such procedures. Suggested working dilutions are given as a guide only. It is recommended that the user titrates the product for use in their own system using appropriate negative/positive controls.
Instructions For Use
View FcSpyCatcher Coupling Protocol

Description Product Code Applications Pack Size List Price Your Price Quantity
SpyTag3 Peptide BLP086 IY 1 mg loader
List Price Your Price
Description SpyTag3 Peptide

Antibody Characterization Reference

  1. Hentrich, C. et al. (2021) Periplasmic expression of SpyTagged antibody fragments enables rapid modular antibody assembly.
    Cell Chem Biol. 28 (6): 813-824.e6.
  2. Zakeri, B. et al. (2012) Peptide tag forming a rapid covalent bond to a protein, through engineering a bacterial adhesin.
    Proc Natl Acad Sci U S A. 109 (12): E690-7.
  3. Keeble, A.H. et al. (2019) Approaching infinite affinity through engineering of peptide-protein interaction.
    Proc Natl Acad Sci U S A. 116(52):26523-33.



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