Recombinant Human Serpin B2/PAI-2 Protein, CF

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Recombinant Human Serpin B2/PAI-2 Protein, CF Summary

Product Specifications

>95%, by SDS-PAGE visualized with Silver Staining and quantitative densitometry by Coomassie® Blue Staining.
Endotoxin Level
<1.0 EU per 1 μg of the protein by the LAL method.
Measured by its ability to inhibit uPA cleavage of a peptide substrate, N-carbobenzyloxy-Gly-Gly-Arg-7-amido-4-methylcoumarin (Z-GGR-AMC).

The inhibition IC50 is <15 nM, as measured under the described conditions.

E. coli-derived human Serpin B2 protein
Glu2-Ala65/Ala99-Pro415, with an N-terminal Met and 6-His tag
Accession #
N-terminal Sequence
Predicted Molecular Mass
44 kDa
41 kDa, reducing conditions

Product Datasheets

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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.


Formulation Supplied as a 0.2 μm filtered solution in Sodium Acetate, NaCl and Chaps.
Shipping The product is shipped with polar packs. Upon receipt, store it immediately at the temperature recommended below.
Stability & Storage: Use a manual defrost freezer and avoid repeated freeze-thaw cycles.
  • 6 months from date of receipt, -70 °C as supplied.
  • 3 months, -70 °C under sterile conditions after opening.

Assay Procedure

  • Assay Buffer: 50 mM Tris, 0.01% Tween® 20, pH 8.5
  • Recombinant Human Serpin B2 (rhSerpin B2) (Catalog # 9206-PI)
  • Recombinant Human u-Plasminogen Activator (uPA)/Urokinase (rhuPA) (Catalog # 1310-SE)
  • Substrate: Z-Gly-Gly-Arg-AMC (Bachem, Catalog # I-1140), 10 mM stock in DMSO
  • F16 Black Maxisorp Plate (Nunc, Catalog # 475515)
  • Fluorescent Plate Reader (Model: Gemini EM by Molecular Devices) or equivalent
  1. Prepare a curve of rhSerpin B2 (MW: 43.8 kDa) in Assay Buffer. Make the following serial dilutions: 400, 200, 100, 50, 25, 12.5, 6.25, 3.125, and 0.3125 nM. 
  2. Dilute rhuPA to 2 μg/mL in Assay Buffer.
  3. Combine equal volumes of each point of the rhSerpin B2 curve with 2 µg/mL rhuPA. Include an enzyme control containing equal volumes of Assay Buffer and rhuPA.
  4. Incubate reaction mixtures at room temperature for 15 minutes.
  5. Dilute Substrate to 200 µM in Assay Buffer.
  6. Load 50 µL of the diluted incubated mixtures into empty wells of a plate, and start the reaction by adding 50 µL of 200 µM Substrate. Include a Substrate Blank containing 50 µL of Assay Buffer and 50 µL of 200 µM Substrate.
  7. Read at excitation and emission wavelengths of 380 nm and 460 nm (top read), respectively, in kinetic mode for 5 minutes.
  8. Derive the 50% inhibition concentration (IC50) value for rhSerpin-B2 by plotting RFU/min (or specific activity) versus concentration with 4-PL fitting.
  9. Calculate specific activity for each point using the following formula (if needed):

     Specific Activity (pmol/min/µg) =

Adjusted Vmax* (RFU/min) x Conversion Factor** (pmol/RFU)
amount of enzyme (µg)

     *Adjusted for Substrate Blank
     **Derived using calibration standard 7-amino, 4-Methyl Coumarin (Sigma, Catalog # A9891)

Per Well:
  • rhSerpin-B2: 100, 50, 25, 12.5, 6.25, 3.125, 1.56, 0.78, and 0.078 nM
  • rhuPA: 0.050 µg
  • Substrate: 100 µM
Reconstitution Calculator

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Background: Serpin B2

Serpin B2, also known as PAI-2, is an approximately 60 kDa serine protease inhibitor (1). It is primarily secreted by macrophages and monocytes (2, 3) and can form disulfide-linked multimers (4, 5). Serpin B2 inhibits both the urokinase-type and tissue-type plasminogen activators (uPA and tPA) (3, 4, 6). Serpin B2 also promotes the clearance of uPA by enhancing its binding and uptake by LRP (7). It limits fibril formation by Huntington protein (HTT) and beta-Amyloid peptides (8). It promotes Th2 biased immune responses and is important for intestinal CCL2 production, monocyte recruitment, and nematode clearance (2, 9). A non-glycosylated form of Serpin B2 is retained intracellularly where it interferes with TNF-a induced apoptosis by protecting the Retinoblastoma protein (RB1) from calpain digestion (10). It also inhibits proteasome activity in activated endothelial cells (11). Serpin B2 is upregulated in HIV-1 infected PBMC, induces RB1 upregulation, and promotes HIV-1 replication (12). Human Serpin B2 shares 76% and 73% amino acid sequence identity with mouse and rat Serpin B2, respectively.

  1. Shea-Donohue, T. et al. (2014) Gut Microbes 5:254.
  2. Schroder, W.A. et al. (2010) J. Immunol. 184:2663.
  3. Ritchie, H. et al. (1999) Thomb. Haemost. 81:96.
  4. Mikus, P. et al. (1993) Eur. J. Biochem. 218:1071.
  5. Wilczynska, M. et al. (2003) EMBO J. 22:1753.
  6. Baker, M.S. et al. (1990) Cancer Res. 50:4676.
  7. Croucher, D. et al. (2006) J. Biol. Chem. 281:10206.
  8. Lee, J.A. et al. (2015) PLoS One 10:e0130136.
  9. Zhao, A. et al. (2013) J. Immunol. 190:5779.
  10. Tonnetti, L. et al. (2008) Cancer Res. 68:5648.
  11. Boncela, J. et al. (2011) J. Biol. Chem. 286:43164.
  12. Darnell, G.A. et al. (2006) J. Biol. Chem. 281:31348.
Entrez Gene IDs
5055 (Human); 18788 (Mouse); 60325 (Rat)
Alternate Names
HsT1201; Monocyte Arg-serpin; PAI; PAI2; PAI2Urokinase inhibitor; Placental plasminogen activator inhibitor; PLANH2; PLANH2PAI-2; plasminogen activator inhibitor 2; plasminogen activator inhibitor, type II (arginine-serpin); serine (or cysteine) proteinase inhibitor, clade B (ovalbumin), member 2; Serpin B2; serpin peptidase inhibitor, clade B (ovalbumin), member 2; Urokinase Inhibitor

Citation for Recombinant Human Serpin B2/PAI-2 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. Cell-Type-Specific Gene Regulatory Networks Underlying Murine Neonatal Heart Regeneration at Single-Cell Resolution
    Authors: Z Wang, M Cui, AM Shah, W Tan, N Liu, R Bassel-Dub, EN Olson
    Cell Reports, 2020;33(10):108472.
    Species: Human
    Sample Types: Whole Cells
    Applications: Bioassay


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