• Purity

  >95%, by SDS-PAGE with silver staining.

• Endotoxin Level

  <0.10 EU per 1 μg of the protein by the LAL method.  

• Activity

  Measured by its ability to induce IL-6 secretion by A375 human melanoma cells. Hibino, T.     et al. (2013) Cancer Res.     73:172. The ED    ₅₀ for this effect is 1.5-6 μg/mL.

• Source

  E. coli-derived Met1-Glu93 (S100A8) & Thr2-Pro114 (S100A9)

• Accession #

• N-terminal Sequence    
  Analysis

  Met1 (S100A8) & Thr2 (S100A9)

• Structure / Form

  Noncovalently-linked heterodimer

• Predicted Molecular Mass

  11 kDa (S100A8) & 13 kDa (S100A9)

• SDS-PAGE

  9 kDa (S100A8) & 13 kDa (S100A9), reducing conditions

Data Images

Background: S100A8/S100A9 Heterodimer

S100A8 (also known as MRP8, Calgranulin A, and CP-10) and S100A9 (also known as MRP14 and Calgranulin B) are pro-inflammatory members of the S100 family of secreted calcium binding proteins (1, 2). They are up-regulated in neutrophils and monocytes at sites of inflammation (e.g. psoriasis, rheumatoid arthritis, cardiac ischemia) and are present at elevated concentrations in rheumatoid arthritis synovial fluid (3-5). The 10 kDa human S100A8 and 14 kDa S100A9 each contain two  
EF‑hand calcium binding motifs. Human S100A8 shares 57% and 61% amino acid (aa) sequence identity with mouse and rat S100A8, respectively. Human S100A9 shares 57% and 62% amino acid sequence identity with mouse and rat S100A9, respectively (6, 7). S100A8 and S100A9 are noncovalent homodimers that can also noncovalently heterodimerize; in the presence of calcium and zinc, the homodimer and heterodimers will form tetramers (8-10). The heterodimer additionally binds and sequesters manganese, thereby restricting the growth of Mn-dependent bacteria (11). The S100A8/A9 heterodimer exhibits functions beyond those performed by the individual proteins. These include binding to fatty acids such as arachidonic acid and promoting astrocyte proliferation (3, 12). S100A8, S100A9, and the heterodimer each promote neutrophil infiltration into sites of inflammation and inflammatory cytokine production by monocytes (4, 5, 9).

• References:

1. Averill, M.M. et al. (2012) Arterioscler. Thromb. Vasc. Biol. 32:223.

2. Vogl, T. et al. (2012) Int. J. Mol. Sci. 13:2893.

3. Siegenthaler, G. et al. (1997) J. Biol. Chem. 272:9371.

4. Sunahori, K. et al. (2006) Arthritis Res. Ther. 8:R69.

5. Volz, H.C. et al. (2012) Basic Res. Cardiol. 107:250.

6. Odink, K. et al. (1987) Nature 330:80.

7. Dorin, J.R. et al. (1987) Nature 326:614.

8. Teigelkamp, S. et al. (1991) J. Biol. Chem. 266:13462.

9. Ryckman, C. et al. (2003) J. Immunol. 170:3233.

10. Vogl, T. et al. (2006) Biochim. Biophys. Acta 1763:1298.

11. Damo, S.M. et al. (2013) Proc. Natl. Acad. Sci. USA 110:3841.

12. Ryu, M-J. et al. (2012) J. Biol. Chem. 287:22948.

• Long Name:

  S100 Calcium Binding Protein A8/S100 Calcium Binding Protein A9

• Entrez Gene IDs:

  6279 (Human)

• Alternate Names:

  Calprotectin; S100A8/S100A9 Heterodimer