Cusabio N-terminal 6xHis-B2M-tagged Recombinant


β2 microglobulin, also known as N-terminal 6xHis beta-2 microglobulin (B2M) tagged Recombinant, is a component of MHC class I molecules that belongs to the beta-2 microglobulin family. B2M is present in all nucleated cells (excludes red blood cells). B2M associates not only with the alpha chain of MHC class I molecules but also with class I-like molecules such as CD1 and Qa.

An additional function of B2M is an association with the protein HFE, which together regulate the expression of hepcidin in the liver that targets the iron transporter ferroportin in the cytoplasmic membrane of enterocytes and macrophages for degradation, resulting in a decrease of iron absorption from food and iron release from recycled red. globules respectively. Loss of this function causes excess iron and hemochromatosis. Defects in B2M are the cause of hypercatabolic hypoproteinemia (HYCATHYP).

Synonymous: B2M


Human B2M, His Tag (B2M-H5225) is expressed from human 293 cells (HEK293). Contains AA Ile 21 – Met 119 (Accession number P61769-1).

Predicted N-terminus: Ile 21

Molecular Characterization

  • This protein carries a polyhistidine tag at the C-terminus.
  • The protein has a calculated MW of 12.6 kDa. The protein migrates as 14 kDa under reducing conditions (R) (SDS-PAGE).

Endotoxin: Less than 1.0 EU per μg by the LAL method.

Purity: >98% as determined by SDS-PAGE.


Lyophilized from a 0.22 µm filtered solution in PBS, pH 7.4. Trehalose is normally added as a protectant before lyophilization.


See the Certificate of Analysis for specific instructions. For best performance, we strongly recommend that you follow the reconstitution protocol provided in the CoA.


For long-term storage, the product should be stored in the freeze-dried state at -20°C or below. Avoid repeated cycles of freezing and thawing.

This product is stable after storage at:

  • -20°C to -70°C for 12 months in the freeze-dried state;
  • -70°C for 3 months under sterile conditions after reconstitution.