Biotinylated human FcRn (FCGRT-B2M) heterodimer protein

Product code: HUFCRN-B

  • 250 μg

    USD 770

  • Availability

    In stock

  • 5x 250 μg

    USD 2860

  • Availability

    In stock

Product description

IgG Fc fragment receptor transporter, also known as the neonatal Fc receptor or more commonly FcRn, consist of two subunits (FCGRT and B2M) and forms an MHC class I-like heterodimer. FcRn binds to the Fc domain of monomeric IgG and mediates the pH dependent recycling of IgG as well as its uptake from milk and transfer from mother to fetus.


Brambell receptor, FCGRT, FCGRT & B2M, FCGRT and B2M, FcRn, Neonatal Fc receptor

QC images

All products are validated by three methods to verify purity and biological activity. See validation section for full details.



Accession number

P55899 / P61769


Not applicable

Conjugation status

Biotinylated. Biotin to protein ratio is confirmed as 0.7-1.0 by the HABA assay. Product has been site-specifically biotinylated using the AVI tag technology, where the lysine residue within the tag is enzymatically labeled with biotin.


>95% monomer purity as determined by SDS-PAGE and SEC-HPLC.


<1.0 EU per mg as determined by the LAL method.

Protein design

The sequence of the extracellular domain of human FCGRT (Ala 24-Ser 297) was fused with a C-terminal tag consisting of the AVI tag, TEV protease recognition sequence and a 10-His tag. This was co-transfected with the sequence of human B2M (Ile 21-Met 119) and the resulting FcRn heterodimer was purified. The full protein sequences can be downloaded from the product webpage.

Molecular weight

The recombinant FcRn heterodimer including tags consists of 412 amino acids and has a theoretical mass of 46570 Da. The heterodimer consists of human FCGRT (313 amino acids; 34839 Da) and human B2M (99 amino acids; 11731 Da).

Expression host

Human embryonic kidney (HEK) 293 cells.


Lyophilized from sterile PBS, pH 7.4. No preservatives or cryoprotectants have been added.


To obtain a final concentration of 1 mg/ml reconstitute 250 μg vials with 250 μl water and 1.0 mg vials with 1.0 ml water. Solubilize for 30 to 60 minutes at room temperature with occasional gentle mixing. Do not vortex.


All recombinant proteins are provided as lyophilized powder and shipped at ambient temperature.

Storage and stability

Lyophilized proteins are stable at ambient temperature for at least 2 weeks. If the protein is not to be used immediately then the protein should be stored in lyophilized form at -20 °C for up 12 months. Once the protein has been reconstituted we recommend storage at 4 °C for up to one week. For longer term storage of protein in solution we recommend aliquoting into smaller vials to avoid repeated freeze-thaw cycles and storage at -20 or -80 °C for up to 3 months. To avoid surface adsorption loss and inactivation we strongly recommend that the protein should not be aliquoted in less than 10 μg per vial.

The below images are examples of data for one batch of this product. Every batch of recombinant proteins is assessed by the same methods and batch specific data is provided in the respective certificate of analysis (COA). COAs can be downloaded from the documentation at the top of this page.

Product purity by SDS-PAGE

Human FcRn on Coomassie Blue stained SDS-PAGE under non-reducing (NR) and reducing (R) conditions. The upper band is the FCGRT 'heavy' chain and the lower band is the B2M 'light' chain. The purity of the protein is greater than 95%.

Product purity by SEC-HPLC

Assessment of protein purity for human FcRn by SEC-HPLC. The protein is greater than 95% pure.

Product activity by SPR

Assessment of binding of human FcRn, immobilized on a CM5 chip via an anti-His antibody, to anti-HER2 human IgG1 (trastuzumab) using a Biacore 8K instrument. The protein binds with an affinity constant (KD) of 147 nM.

The neonatal Fc receptor (FcRn) is an approximately 45 kDa transmembrane glycoprotein with structural homology to MHC class I proteins. It is widely expressed in endothelial and epithelial cells and plays an important role in IgG homeostasis and antigen presentation by dendritic cells. FcRn is a heterodimer composed of a heavy chain, known as p51 or FCGRT, and a light chain, known as p14 or beta-2-microglobulin (β2M). FcRn has non-overlapping binding sites for the IgG Fc domain and albumin, which both mind to FcRn at mildly acidic pH (approximately pH 6.0) but not at neutral pH (approximately pH 7.4). FcRn cycles between the plasma membrane and acidified intracellular compartments of endothelial cells. It binds endocytosed IgG and albumin in the low pH vesicles and transports them to the plasma membrane for extracellular release at higher pH, as shown in the image below. This protects IgG and albumin from lysosomal degradation and helps maintain the circulating levels of both proteins.

For further information on the structure and functions of FcRn please see our FcRn resource page.


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Product code: HUFCRN-B

  • 250 μg

    USD 770

  • Availability

    In stock

  • 5x 250 μg

    USD 2860

  • Availability

    In stock

Additional formats or allotypes

Human FcRn (FCGRT-B2M) heterodimer protein

Panel of all human Fc receptors

Save over 30% by purchasing a full set of all human Fc gamma receptors, including all allotypes and FcRn

  • Unconjugated

  • 1 mg of each FcR

    USD 4620

  • 5x1 mg of each FcR

    USD 17160

  • Biotinylated

  • 250 μg of each FcR

    USD 4620

  • 5x 250 μg of each FcR

    USD 17160

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