Recombinant Human CRP (carrier-free)

Pricing & Availability
Regulatory Status
Other Names
C-reactive protein (CRP), Pentraxin 1 (PTX1)
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Product Citations
Recombinant human CRP, when immobilized, is able to bind recombinant human APCS in a dose dependent manner. The BD50 is 0.1 - 0.4 µg/mL.
  • CRP_Human_RECOM_BA_102914
    Recombinant human CRP, when immobilized, is able to bind recombinant human APCS in a dose dependent manner. The BD50 is 0.1 - 0.4 µg/mL.
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557004 25 µg 90€
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557006 100 µg 175€
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C-reactive protein (also known as CRP and Pentraxin 1 (PTX1)), is a member of pentraxin protein family. Similar to other pentraxins, CRP is a pattern recognition molecule that is able to recognize pathogens and promote their clearance. CRP tends to form a non-covalently linked pentamer with each subunit made up of two antiparallel β-sheets and a single short α-helix. It is characterized by the presence of a cleft that extends from the center of the subunit to its edge at the central pore of the pentamer structure. It has been demonstrated that CRP binds to the phosphocholine moieties expressed on the surface of dead or dying cells and some bacteria. This leads to the activation of the complement system and promotion of phagocytosis by macrophages to clear necrotic and apoptotic cells. CRP is secreted by hepatocytes and is a biomarker for inflammation. IL-6 has been shown to be an effective inducer of this protein. Besides binding to apoptotic cells, CRP also binds to a variety of molecules including C1q, bacterial polysaccharide, CD64, CD32, APCS, HDL, and fibronectin. In addition to participating in immune responses, CRP is also a prominent partaker in endothelial dysfunction and atherosclerosis. It was shown that CRP may exhibit direct proantherogenic effects by upregulating angiotensin type I receptor in smooth muscle cells and promoting their migration, proliferation, neointimal formation, and reactive oxygen species production. Mature human CRP shares 71% amino acid sequence homology with its mouse counterpart.

Product Details
Technical Data Sheet (pdf)

Product Details

Human CRP, amino acids (Phe17-Pro224) (Accession# NP_000558), was expressed in E. coli with an additional Met at the N-terminus.
Molecular Mass
The 209 amino acid recombinant protein has a predicted molecular mass of approximately 23 kD. The protein migrates approximately at 26 kD in DTT-reducing and non-reducing conditions by SDS-PAGE. The predicted N-terminal amino acid is Met.
>95%, as determined by Coomassie stained SDS-PAGE.
0.22 µm filtered protein solution is in 20 mM Tris, 150 mM NaCl, 2 mM CaCl2, and pH 7.5.
Endotoxin Level
Less than 0.1 EU per µg of protein as determined by the LAL method.
10 and 25 µg sizes are bottled at 200 µg/mL. 100 µg size and larger sizes are lot-specific and bottled at the concentration indicated on the vial. To obtain lot-specific concentration, please enter the lot number in our Concentration and Expiration Lookup or Certificate of Analysis online tools.
Storage & Handling
Unopened vial can be stored between 2°C and 8°C for up to 2 weeks, at -20°C for up to six months, or at -70°C or colder until the expiration date. For maximum results, quick spin vial prior to opening. The protein can be aliquoted and stored at -20°C or colder. Stock solutions can also be prepared at 50 - 100 µg/mL in appropriate sterile buffer, carrier protein such as 0.2 - 1% BSA or HSA can be added when preparing the stock solution. Aliquots can be stored between 2°C and 8°C for up to one week and stored at -20°C or colder for up to 3 months. Avoid repeated freeze/thaw cycles.
Human CRP, when immobilized at 2 µg/mL, is able to bind recombinant APCS in a dose-dependent manner with a median binding affinity (BD50) of 0.1 - 0.4 µg/mL.


Application Notes

Bioassay Protocol

  1. Human CRP was immobilized on an ELISA plate at a concentration of 2 µg/mL (100 µL well with a coating buffer of 50 mM Tris, 150 mM NaCl, 1 mM CaCl2, and pH 7.5). The wells were blocked with coating buffer that contained 3% BSA before being used in the binding assays.
  2. The binding assay was performed with various concentrations of hAPCS-biotin using coating buffer containing 3% BSA at 4°C overnight.
  3. Wells were washed with coating buffer containing 0.3% BSA four times.
  4. Avidin-HRP at 1:2000 in coating buffer containing 0.3% BSA was used to detect hAPCS-biotin bound to immobilized hCRP.

BioLegend carrier-free recombinant proteins provided in liquid format are shipped on blue-ice. Our comparison testing data indicates that when handled and stored as recommended, the liquid format has equal or better stability and shelf-life compared to commercially available lyophilized proteins after reconstitution. Our liquid proteins are verified in-house to maintain activity after shipping on blue ice and are backed by our 100% satisfaction guarantee. If you have any concerns, contact us at

Product Citations
  1. Kisielow J, et al. 2019. Nat Immunol. 1.286111111. PubMed

Antigen Details

Monomer and homopentamer.
Human CRP induces expression of E-selectin and VCAM-1 expression in epithelial cells. CRP binds to target initiates and regulates complement activation.
Phosphocholine on the surface of apoptotic cells.
Interacts with C1q, bacterial polysaccharide, CD64, CD32, APCS (PTX2), HDL, leptin, and fibronectin.
Human CRP is able to bind recombinant human APCS in a dose dependent manner in the presence of Ca2+.
Biology Area
Cell Biology, Immunology, Innate Immunity
Antigen References

1. Ansar W and and Ghosh S. 2013. Immunol. Res. 56:131.
2. Agrawal A, et al. 2009. Adv. Exp. Med. Biol. 653:98.
3. Garlanda C, et al. 2005. Annu. Rev. Immunol. 23:337.
4. Verma S, et al. 2004. Circulation 109:1914.
5. Wadham C, et al. 2004. Circulation 109:2116.
6. Li XA, et al. 1998. Biochem. Biophys. Res. Commun. 244:249.
7. Lu J, et al. 2012. Immunol. Rev. 250:230.
8. Chen K, et al. 2006. Nat. Med. 12:425.

Gene ID
1401 View all products for this Gene ID
View information about CRP on

Related FAQs

Why choose BioLegend recombinant proteins?

     • Each lot of product is quality-tested for bioactivity as indicated on the data sheet.
     • Greater than 95% Purity or higher, tested on every lot of product.
     • 100% Satisfaction Guarantee for quality performance, stability, and consistency.
     • Ready-to-use liquid format saves time and reduces challenges associated with reconstitution.
     • Bulk and customization available. Contact us.
     • Learn more about our Recombinant Proteins.

How does the activity of your recombinant proteins compare to competitors?

We quality control each and every lot of recombinant protein. Not only do we check its bioactivity, but we also compare it against other commercially available recombinant proteins. We make sure each recombinant protein’s activity is at least as good as or better than the competition’s. In order to provide you with the best possible product, we ensure that our testing process is rigorous and thorough. If you’re curious and eager to make the switch to BioLegend recombinants, contact your sales representative today!

What is the specific activity or ED50 of my recombinant protein?

The specific activity range of the protein is indicated on the product datasheets. Because the exact activity values on a per unit basis can largely fluctuate depending on a number of factors, including the nature of the assay, cell density, age of cells/passage number, culture media used, and end user technique, the specific activity is best defined as a range and we guarantee the specific activity of all our lots will be within the range indicated on the datasheet. Please note this only applies to recombinants labeled for use in bioassays. ELISA standard recombinant proteins are not recommended for bioassay usage as they are not tested for these applications.

Have your recombinants been tested for stability?

Our testing shows that the recombinant proteins are able to withstand room temperature for a week without losing activity. In addition the recombinant proteins were also found to withstand four cycles of freeze and thaw without losing activity.

Does specific activity of a recombinant protein vary between lots?

Specific activity will vary for each lot and for the type of experiment that is done to validate it, but all passed lots will have activity within the established ED50 range for the product and we guarantee that our products will have lot-to-lot consistency. Please conduct an experiment-specific validation to find the optimal ED50 for your system.

How do you convert activity as an ED50 in ng/ml to a specific activity in Units/mg?
Use formula Specific activity (Units/mg) = 10e6/ ED50 (ng/mL)
Go To Top Version: 1    Revision Date: 10/31/2014

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*These products may be covered by one or more Limited Use Label Licenses (see the BioLegend Catalog or our website, BioLegend products may not be transferred to third parties, resold, modified for resale, or used to manufacture commercial products, reverse engineer functionally similar materials, or to provide a service to third parties without written approval of BioLegend. By use of these products you accept the terms and conditions of all applicable Limited Use Label Licenses. Unless otherwise indicated, these products are for research use only and are not intended for human or animal diagnostic, therapeutic or commercial use.


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