Recombinant human FcRn/FCGRT & B2M Heterodimer Protein, 2 x 50µg

Background
FCGRT & B2M heterodimer protein (FcRn complex) consist of two subunits: p51 (equivalent to FCGRT), and p14 (equivalent to beta-2-microglobulin), and forms an MHC class I-like heterodimer. Fc fragment of IgG, receptor, transporter, alpha (FCGRT) binds to the Fc region of monomeric immunoglobulins gamma and mediates the uptake of IgG from milk. FCGRT possible role in transfer of immunoglobulin G from mother to fetus. Beta-2-microglobulin (B2M) is a component of the class I major histocompatibility complex (MHC) and involved in the presentation of peptide antigens to the immune system.

Source
Recombinant Human FCGRT & B2M heterodimer protein (Human FCGRT & B2M) Ala 24 - Ser 297 (FCGRT, NP_001129491.1) and & Ile 21 - Met 119 (B2M, AAH32589) was produced in human 293 cells (HEK293)

Molecular Characterization
FcRn(Ala 24 - Ser 297 (FCGRT) & Ile 21 - Met 119 (B2M)) NP_001129491.1 (FCGRT) & AAH32589 (B2M)
Human FcRn / FCGRT & B2M heterodimer protein, produced by co-expression of FCGRT and B2M, has a calculated MW of 31.2 kDa FCGRT and 13.1 kDa (B2M). Subunit FCGRT is fused with his-tag at the C-terminus and subunit Beta-2 microglobulin (B2M) is fused with Strep II-tag at the C-terminus. The predicted N-terminus is Ala 24(FCGRT) & Ile 21(B2M). The reducing (R) protein migrates as 33 kDa (FCGRT) and 13 kDa (B2M) respectively due to glycosylation.

Endotoxin
Less than 1.0 EU per μg of the Human FcRN & B2M by the LAL method.

Purity
>95% as determined by SDS-PAGE. The purity of Human FcRN & B2M was determined by reduced SDS-PAGE and staining overnight with Coomassie Blue.

Formulation
Lyophilized from 0.22 μm filtered solution in PBS, pH7.4. Normally Mannitol or Trehalose are added as protectants before lyophilization.

Reconstitution
See Certificate of Analysis for details of reconstitution instruction and specific concentration.

Storage
Avoid repeated freeze-thaw cycles. No activity loss was observed after storage at:
In lyophilized state for 1 year (4C-8C); After reconstitution under sterile conditions for 1 month (4C-8C) or 3 months (-20C to -70C).

Bioactivity
Measured by its binding ability in a functional ELISA. Immobilized Yervoy Ipilimumab (Human IgG1) at 10 μg/mL (100 μL/well) can bind Human FcRn / FCGRT & B2M (Cat# FCM-H5286 ) with a linear range of 0.06-5 μg/mL (QC tested). Immobilized Human FcRn / FCGRT & B2M Heterodimer Protein (Cat# FCM-H5286) can bind human IgG1 with an affinity constant of 1 μM as determined in a SPR assay (Biacore 2000). The data is generally provided by Biaffin GmbH &Co KG, Germany (Routinely tested).

References

(1) Goebl NA., et al., 2008, Mol. Biol. Cell 19 (12): 5490–505.
(2) Lee TY., et al., 2008, Clin. Cancer Res. 14 (5): 1487–93.
(3) Güssow D., et al., 1987, J. Immunol. 139 (9): 3132–8.
(4) Gorevic P.D., et al., 1986, Proc. Natl. Acad. Sci. U.S.A. 83:7908-7912.