Recombinant human FGF-2 (145 aa) protein (Qk025)

Product: Qk025 Category:

Price range: £150.00 through £735.00

Qk025 FGF-2 145 aa vial image
Qk027 FGF-2 145 aa SDS page purity
Qk025 FGF-2 bioactivity graph
Recombinant human FGF-2 (145 aa) protein (Qk025) - Image 4

Human fibroblast growth factor 2 (FGF-2/bFGF) protein (145 aa) is our gold-standard and recommended FGF-2 / bFGF protein for induced pluripotent stem cell (iPSC) and embryonic stem cell (ESC) maintenance, and iPSC and mesenchymal stem cell (MSC) proliferation and differentiation.

Highly pure and bioactive 17 kDa FGF-2 protein animal origin-free (AOF) and carrier protein-free (CF) comprising the core structured region (145 aa) sufficient for full biological activity.

Qkine FGF-2 is also available as cell therapy grade with extended quality testing and documentation – Qk025-CTG

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Price range: £150.00 through £735.00

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1000 µg will be dispatched as 2 x 500 µg.

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Summary:

  • High purity human FGF-2 / basic FGF, 145 aa form comprising residues 144-288 (Uniprot: P09038)
    •
  • 17 kDa

  • >98%, by SDS-PAGE quantitative densitometry

  • Expressed in E. coli

  • Animal origin-free (AOF) and carrier protein-free

  • Manufactured in our Cambridge, UK laboratories

  • Lyophilized from Tris, NaCl, CyS, mannitol

  • Resuspend in sterile-filtered water at >50 µg/ml, add carrier protein if desired, prepare single use aliquots and store frozen at -20 °C (short-term) or -80 °C (long-term).
Handling and storage FAQ

Featured applications:

  • Expansion of induced pluripotent, embryonic and mesenchymal stem cells

Alternative protein names
Species reactivity
Frequently used together
Related discovery kits
Alternative proteins

FGF-2 activity was determined using the Promega serum response element luciferase reporter assay (*) in transfected HEK293T cells. Cells were treated in triplicate with a serial dilution of FGF-2 for 6 hours. Firefly luciferase activity is measured and normalized to the control Renilla luciferase activity. Data from Qk025 lot #204706. EC50 = 0.24 ng/ml (14 pM).

FGF-2 migrates as major band at 17 kDa in non-reducing (-βME) conditions and upon reduction (+βME). The higher molecular mass band at 35 kDa is a dimer that we always see in our highly purified human FGF-2, the presence of this does not affect biological activity. Purified recombinant protein (7 µg) was resolved using 15% w/v SDS-PAGE in reduced (+β-mercaptothanol, R) and non-reduced conditions (NR) and stained with Coomassie Brilliant Blue R250.  Data from Qk025 lot #014

Further quality assays

  • Mass spectrometry: single species with expected mass

  • Recovery from stock vial:  >95%

  • Endotoxin: <0.05 EU/μg protein

MSDS file

We are a company founded and run by scientists to provide a service and support innovation in stem cell biology and regenerative medicine.  All our products are exceptionally high purity, with complete characterisation and bioactivity analysis on every lot.

Qkine human FGF-2 145 aa was found to be more bioactive than that from an alternative major supplier. Bioactivity was determined using the Promega serum response element luciferase reporter assay in transfected HEK293T cells. Cells were treated in triplicate with a serial dilution of Qkine FGF-2 (Qk025, green) or alternative supplier FGF-2 (Supplier B, black) for 3 hours. Firefly luciferase activity was measured and normalized to control Renilla luciferase activity. Data from Qk025 lot #204697.

Technote | FGF-2 145 aa

Protein background

Fibroblast growth factors (FGFs) are a family of growth factors which regulate a wide range of essential biological functions including cell proliferation and survival, migration and differentiation [1]. The human FGF family has 18-22 members grouped into 6-7 subfamilies based on sequence homology and phylogeny [2]. The FGF family of growth factors have critical roles during both vertebrate and invertebrate embryonic development, in adult cells they modulate tissue maintenance, wound healing and angiogenesis [1,2].

The FGF ligands bind to 4 receptors (FGFR1-4), transmembrane receptors with intracellular tyrosine kinase activity [2, 3]. Once activated FGFRs recruit Src homology-2 (SH2) or phosphotyrosine binding (PTB) domain-containing signaling proteins leading to activation of intracellular signaling pathways [1]. The main signaling pathways activated by FGF binding are the RAS/MAP kinase pathway, PI3 kinase/Akt pathway, and PLCγ pathways [1-3].

Fibroblast growth factor 2 (FGF-2) also known as basic fibroblast growth factor (bFGF) has a broad range of physiological roles including regulation of cell growth, survival and proliferation. FGF-2 is one of the FGFs which binds to and signals through all four of the FGFRs [4].

FGF-2 is an essential growth factor for the maintenance of pluripotency in human embryonic stem cells (ESCs), induced pluripotent stem cells (iPSCs) [4] and mesenchymal stem cells (MSCs) [5]. FGF-2 preserves pluripotency through interaction with PI3 kinase/Akt, ERK1/2, JAK/STAT and PLCγ pathways by activation of activin A. In feeder culture systems FGF-2 stimulates production of essential growth factors and cytokines from the feeder layer [5].

FGF-2 and TGFβ1 are required for maintenance of iPSC in feeder free culture, Qkine produces high quality, bioactive and animal origin-free FGF-2 (Qk025) and TGF-β1 (Qk010) for stem cell culture. However, FGF-2 has poor thermostability in culture so, to prevent the need for daily media changes, Qkine FGF2-G3 has been engineered to be highly thermostable allowing weekend-free culture of iPSCs.

Background references

Additional resources

Publications using Recombinant human FGF-2 (145 aa) protein (Qk025)

  • Hydrostatic pressure promotes chondrogenic differentiation and microvesicle release from human embryonic and bone marrow stem cells

    Luo L, Foster NC, Man KL et al.

    DOI: doi: 10.1002/biot.202100401

  • Refined and benchmarked homemade media for cost-effective, weekend-free human pluripotent stem cell culture

    Truszkowski L, Bottini S, Bianchi S et al. 

    DOI: doi.org/10.12688/openreseurope.18245.2

  • Pervanadate-induced oxidation relieves autoinhibition of SRC protein tyrosine kinase

    Mulholland KE, Bourguet M, Cheng N et al.

    DOI: doi.org/10.1101/2025.04.27.650842

FAQ

What is FGF-2?

Fibroblast growth factor 2 (FGF-2), also known as basic fibroblast growth factor (bFGF) is a growth factor and signaling protein.

Where is FGF-2 found?

FGF-2 is expressed in a developmental and tissue specific manner. It’s expression is tightly controlled in normal tissues and it can be detected in all major tissues.

What does FGF-2 do?

FGF-2 is essential for normal embryonic development. It has roles in cell survival and proliferation, angiogenesis, tumorigenesis, wound healing and tissue repair.

What does FGF-2 bind to?

FGF-2 binds to and signals though all four of the FGF receptors FGFR1-4.

What is the function of the FGF receptor?

FGFRs phosphorylate specific tyrosine residues and activate the RAS-MAPK, PI3K-AKT, PLCγ, and STAT intracellular signaling pathways.

How is FGF-2 used in stem cell culture?

FGF-2 is used to maintain the pluripotency of stem cells in culture.

Why is our truncated FGF-2 145 amino acids rather than 146 amino acids?

We offer the 145 amino acid form rather than the 146 due to the E. coli processing of the N-terminal. When the 146 form (Pro143-Ser288) is expressed, the proline is either partially or completely removed. To improve expression in E. coli, we chose to start with the alanine (Ala144-Ser288) form. This modification does not affect receptor binding or bioactivity.

Other listings of the 146 amino acid form will often be a mixture of FGF-2 146 and 145, or, in some cases, only the 145 form.

What is the difference between FGF-2 145 aa and 154 aa?

Fibroblast Growth Factor 2 (FGF-2) exists in two main isoforms, distinguished by length: 145 amino acids (aa) and 154 aa. The 154 aa variant contains an additional nine amino acids at the N-terminus. While this extension is not essential for biological activity, it may influence the protein’s localization within cells.
Key differences between the isoforms:
  • FGF-2 (145 aa):
    • The most widely used form, supporting proliferation and survival of stem and progenitor cells.
    • Commonly preferred for organoid culture due to its robust activity and well-established performance.
  • FGF-2 (154 aa):
    • Contains an N-terminal extension that may affect intracellular localization or signaling.
    • Typically, not required for standard organoid or stem cell maintenance, unless specific signaling or localization effects are being investigated.

What is FGF2-G3 (FGF2-STAB®)?

Recombinant FGF2-G3 (FGF2-STAB®) is a thermostable, engineered form of FGF-2 (bFGF). This modification significantly increases the protein’s functional half-life — from <10 hours for wild-type FGF-2 to >7 days for FGF2-G3 — improving stability and consistency in culture systems.

Our products are for research use only and not for diagnostic or therapeutic use. Products are not for resale.

For use in manufacturing of cellular or gene therapy products. Not intended for in vivo applications.

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Qk025 FGF-2 145 aa vial imageRecombinant human FGF-2 (145 aa) protein (Qk025)
Price range: £150.00 through £735.00View product