Recombinant Human PA28 Activator alpha Subunit Protein, CF

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R&D Systems Recombinant Proteins and Enzymes
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Recombinant Human PA28 Activator alpha Subunit Protein, CF Summary

Product Specifications

>95%, by SDS-PAGE under reducing conditions and visualized by Colloidal Coomassie® Blue stain
Recombinant Human PA28 Activator alpha Subunit is ideal for the activation of latent 20S Proteasome complexes. Reaction conditions will need to be optimized for each specific application. Initially, we recommend a 5- to 15-fold molar excess of Recombinant Human PA28 Activator alpha Subunit relative to 20S Proteasome.
E. coli-derived human PA28 Activator alpha Subunit protein
Accession #
Predicted Molecular Mass
29 kDa

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Carrier Free

What does CF mean?

CF stands for Carrier Free (CF). We typically add Bovine Serum Albumin (BSA) as a carrier protein to our recombinant proteins. Adding a carrier protein enhances protein stability, increases shelf-life, and allows the recombinant protein to be stored at a more dilute concentration. The carrier free version does not contain BSA.

What formulation is right for me?

In general, we advise purchasing the recombinant protein with BSA for use in cell or tissue culture, or as an ELISA standard. In contrast, the carrier free protein is recommended for applications, in which the presence of BSA could interfere.



X mg/ml (X µM) in 50 mM Hepes, pH 8.0, 200 mM NaCl, 1mM DTT.

Shipping The product is shipped with dry ice or equivalent. Upon receipt, store it immediately at the temperature recommended below.
Stability & Storage: Use a manual defrost freezer and avoid repeated freeze-thaw cycles.
  • 12 months from date of receipt, -70 °C as supplied.
  • 3 months, -70 °C under sterile conditions after opening.
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Background: PA28 Activator alpha Subunit

The Proteasome Activator 28 (PA28) Regulatory Complex, also known as the 11S Regulatory (REG) Complex, is a ring-shaped, multimeric, ATP-independent regulatory complex that can bind to one or both ends of the 20S Proteasome or 20S Immunoproteasome (1,2). The PA28 Regulatory Complex stimulates the proteasome to hydrolyze small peptides, but not ubiquitinated proteins, for the production of peptides for MHC class I antigen presentation (3-7). Three PA28 Regulatory Complex subunits, alpha, beta, and gamma, have been identified and can oligomerize to form the PA28 Regulatory Complex (8-10). While the expression of the PA28 alpha and beta subunits are induced by IFN-gamma, the PA28 gamma subunit is not significantly affected (11,12).  In vivo, PA28 alpha forms hetero-heptamers or -hexamers with PA28 beta (13-15). PA28 alpha can also form active homo-heptamers in vitro and can be used to activate the 20S Proteasome (3,16). In addition to regulating production of MHC class I antigens, PA28 alpha may protect against oxidative stress (17).

  1. Cascio, P. et al. (2002) EMBO J. 21:2636.
  2. Shibatani, T. et al. (2006) Mol. Biol. Cell 17:4962.
  3. Ma, C.P. et al. (1992) J. Biol. Chem. 267:10515.
  4. Wilk, S. et al. (2000) Arch. Biochem. Biophys. 383:265.
  5. Knowlton, J.R. et al. (1997) Nature 390:639.
  6. Groettrup, M. et al. (1996) Nature 381:166.
  7. Dick, T.P. et al. (1996) Cell 86:253.
  8. Kuehn, L. & B. Dahlmann (1997) Mol. Biol. Rep. 24:89.
  9. Li, J. & M. Rechsteiner (2001) Biochimie 83:373.
  10. Realini, C. et al. (1997) J. Biol. Chem. 272:25483.
  11. Jiang, H. & J.J. Monaco (1997) Immunogenetics 46:93.
  12. Ahn, J.Y. et al. (1995) FEBS Lett. 366:37.
  13. Zhang, Z. et al. (1999) Biochemistry 38:5651.
  14. Song, X. et al. (1996) J. Biol. Chem. 271:26410.
  15. Mott, J.D. et al. (1994) J. Biol. Chem. 269:31466.
  16. Johnston, S.C. et al. (1997) Protein Sci. 6:2469.
  17. Li, J. et al. (2011) FASEB J. 25:883.
Long Name
Proteasome (Prosome, Macropain) Activator Subunit 1
Entrez Gene IDs
5720 (Human); 19186 (Mouse); 29630 (Rat)
Alternate Names
11S regulator complex alpha subunit; 11S Regulator Complex Subunit alpha; 29-kD MCP activator subunit; IFI5111; IFI5111MGC8628; IGUP I-5111; Interferon gamma up-regulated I-5111 protein; interferon-gamma IEF SSP 5111; interferon-gamma-inducible protein 5111; PA28 Activator alpha Subunit; PA28A; PA28alphaActivator of multicatalytic protease subunit 1; proteasome (prosome, macropain) activator subunit 1 (PA28 alpha); Proteasome activator 28 subunit alpha; proteasome activator complex subunit 1; proteasome activator subunit-1; PSME1; REG alpha; REGalpha; REG-alpha

Citation for Recombinant Human PA28 Activator alpha Subunit Protein, CF

R&D Systems personnel manually curate a database that contains references using R&D Systems products. The data collected includes not only links to publications in PubMed, but also provides information about sample types, species, and experimental conditions.

1 Citation: Showing 1 - 1

  1. Structure- and function-based design of Plasmodium-selective proteasome inhibitors.
    Authors: Li H, O'Donoghue A, van der Linden W, Xie S, Yoo E, Foe I, Tilley L, Craik C, da Fonseca P, Bogyo M
    Nature, 2015;530(7589):233-6.
    Species: Human
    Sample Types: Protein
    Applications: Enzyme Assay


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