Recombinant Human Activin R1B/ALK-4-Fc Chimera (carrier-free)

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Other Names
Activin Receptor-Like Kinase 4(ALK4), Serine/Threonine-Protein Kinase Receptor R2 (SKR2), Activin A Receptor, Type IB (ACTRIB), ACVRLK4, Activin Receptor Type IB.
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Product Citations
Immobilized recombinant human Activin R1B/ ALK-4 binds human recombinant Cripto in a dose dependent manner. The ED50 = 1 – 5 ng/ml.
  • Human_Activin_R1B-ALK4_RECOM_FC_Chimera_1_012318
    Immobilized recombinant human Activin R1B/ ALK-4 binds human recombinant Cripto in a dose dependent manner. The ED50 = 1 – 5 ng/ml.
  • Human_Activin_R1B-ALK4_RECOM_FC_Chimera_2_012318
    Stability testing for human Activin R1B / ALK-4. Human Activin R1B/ ALK-4 was aliquoted in PBS, pH 7 at 0.2 mg/ml and one aliquot was kept at 4°C (control), and another was freeze/thawed four times (4x freeze-thaws). After this procedure, the samples were tested by functional ELISA. Immobilized recombinant human Activin R1B/ ALK-4 at 5 µg/ml binds human recombinant Cripto in a dose dependent manner.
Cat # Size Price Save
770402 10 µg ¥13,500
770404 25 µg ¥24,300
770406 100 µg ¥63,000
770408 500 µg ¥252,000

The transforming growth factor- (TGF ) superfamily control a big number of biological responses and play a prominent role during embryonic development, regulation of cell growth, differentiation, and apoptosis. 40 distinct TGF members have been identified in vertebrates and they are generally divided into two branches, the TGF /activin/nodals and the bone morphogenetic proteins (BMPs). Activin A is a morphogen during embryonal development, regulating chondrogenic and osteogenic differentiation of mesenchymal progenitor cells (MPC).  Activin A binds two type I and two type II serine/threonine kinase receptors. The type I receptors are named activin receptor-like kinases 1 to 7 (ALK1~7) and Activins bind to ALK4 and ALK7.The type II receptor kinase is constitutively active and phosphorylates the type I receptor after the formation of the ligand-receptor complex.  Five type II receptors have been identified: ActRIIA, ActRIIB, BMPRII, TGFβRII, and MISRII. Activin A binds to ALK-4 and ActRIIB. Activin Recptor 1B (ALK-4) interacts with different ligands. The complex myostatin/activin type I receptor (ALK4) is a mediator of muscle atrophy and muscle regeneration. In addition, cripto binds to cell surface ALK4 expressed on mammalian epithelial cells, and activates nodal- and ALK4-dependent and -independent signaling pathways.

Product Details
Technical data sheet

Product Details

Human Activin R1B amino acids (Leu32 – Glu126) (Accession # AAA60556) was expressed in CHO cells. The carboxy terminus contains SRIEGRMD + hIgG1 Fc (Pro100-Lys330) + 6His tag.
Molecular Mass
The 340 amino acid recombinant protein has a predicted molecular mass of approximately 38.3 kD. The DTT-reduced and non-reduced protein migrate at approximately 45kD and 90 kD by SDS-PAGE respectively. The predicted N-terminal amino acid is Leu.
> 95% by SDS-PAGE gel as determined by Coomassie stained SDS-PAGE.
0.22 µm filtered protein solution is in PBS pH 7.2.
Endotoxin Level
Less than 0.1 EU per µg cytokine as determined by the LAL method.
10 and 25 µg sizes are bottled at 200 µg/mL. 100 µg and larger sizes are lot-specific and bottled at the concentration indicated on the vial (please contact technical support for concentration, or use our Lookup tool if you have a lot number.)
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.
Immobilized recombinant human Activin R1B/ ALK-4 at 5 µg/ml binds human recombinant Cripto in a dose dependent manner. The ED50 = 1 – 5 ng/ml.


Application Notes

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

Antigen Details


Expressed in multiple cell types, neurons, mammary gland, muscle cells, fibroblasts.

Neuronal survival and differentiation, pituitary gland FSH production, wound healing, carcinogenesis, muscle growth, metabolism, and fibrosis.
Activin A, Cripto, Nodal, Myostatin.
Biology Area
Stem Cells
Molecular Family
Soluble Receptors
Antigen References
  1. Hashimotto M, et al. 1992. J Biol Chem. 267:4999.
  2. Cárcamo J, et al. 1994. Mol Cell Biol. 14:3810.
  3. Shav-Tal Y and Zipori D. 2002. Stem Cells. 20:493.
  4. Bianco C, et al. 2003. Cancer Res. 63:1192.
  5. Dojhi T, et al. 2005. Gastroenterology. 128:411.
  6. Tsuchidak K, et al. 2008. Endocr J. 55:11.
  7. Djouad F, et al. 2010. Steam Cell Research. 1:11.
  8. Sako D, et al. 2010. J Biol Chem. 285:21037.
  9. SJones CP, et al. 2012. J Allergy Clin Immuno. 129:1000
  10. Kemaladewi DU, et al. 2012. FASEB J. 26:1462.
  11. Pasteuning-Vuhman, et al. 2017. FASEB. 31:238.
Gene ID
91 View all products for this Gene ID
View information about Activin R1B/ALK-4 Fc-Chimera 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: 01/24/2018

For research use only. Not for diagnostic use. Not for resale. BioLegend will not be held responsible for patent infringement or other violations that may occur with the use of our products.


*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.


BioLegend Inc., 8999 BioLegend Way, San Diego, CA 92121
Toll-Free Phone: 1-877-Bio-Legend (246-5343) Phone: (858) 768-5800 Fax: (877) 455-9587

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