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You are here:Home » Molecular Biology » MB-Growth Factors-FGF » Fibroblast growth factor 21, Recombinant, Human (FGF-21)

Fibroblast growth factor 21, Recombinant, Human (FGF-21)


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Human FGF-21 Fibroblast growth factor 21 (FGF-21) is a member of the FGF gene family, which currently contains 22 human members. Based on its structure, it is further classified as an FGF19 subfamily member. This subfamily includes FGF-19, -21, and -23. Like all other FGF subfamilies, FGF-19 subfamily members contain a 120 amino acid (aa) core FGF domain that exhibits a b-trefoil structure (1, 2). Unlike other FGF subfamilies, FGF-19 subfamily members apparently exhibit poor binding to ECM, resulting in highly diffusible molecules (3). The c-DNA for FGF-21 predicts a 209 aa polypeptide that contains a 28 aa signal sequence and a 181 aa mature region (4). Notably, FGF-21, as well as FGF-19 shows limited binding to heparin (4). One potential alternate splice form has been reported. It shows a 43 aa substitution for the C-terminal 12 aa of the standard form (5). Mature human FGF-21 shows 81% aa identity to mouse FGF-21, and is known to be active on mouse cells (4, 6). The FGF-19 subfamily is considered endocrine in nature. All three subfamily members impact some aspect of metabolism, all three are induced by a nuclear receptor heterodimer that includes RXR, and all three utilize Klotho family members for signal transduction (7, 8, 9). FGF-21 is produced by hepatocytes in response to free fatty acid (FFA) stimulation of a PPARa/RXR dimeric complex (3, 7, 10, 11). This situation occurs clinically during starvation, or following the ingestion of a high-fat/low-carbohydrate diet. Upon FGF-21 secretion, white adipose tissue is induced to release FFAs from triglyceride stores. Once FFAs reach hepatocytes, they are oxidized and reduced to acetyl-CoA. The acetyl-CoA is recombined into 4-carbon ketone bodies (acetoacetate and b-hydroxybutyrate), released, and transported to peripheral tissues for TCA processing and energy generation (11, 12).
A DNA sequence encoding the mature human FGF-21 (His 29-Ser 209; Accession # Q9NSA1) was fused with 5X histidines at the N-terminus. The protein was expressed in E. coli.
Catalog #F4212-93A
Molecular Mass Based on N-terminal amino acid sequencing, the recombinant human FGF-21 starts at the histidine tag and has a predicted molecular mass of approximately 20.2kD.
Endotoxin Level 1 EU/ug of the protein as determined by the LAL method.
Biological ActivityMeasured by its ability to stimulate the proliferation of NIH3T3 cells. The ED 50 for this effect is typically 0.12-0.6ug/ml in the presence of 5ug/ml of rmKlotho-beta
Measured in a cell proliferation assay using human FGF RIIIc transfected BaF3 mouse pro­B cells. The ED50 for this effect is typically 0.06 ­ 0.4ug/ml in the presence of rmKlotho-beta
Storage and Stability:
Lyophilized powder stored at -20°C to -70°C is stable for 12 months. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Product reconstituted under sterile conditions is stable for 1 month at 4°C and for 3 months at --20°C to -70°C. Avoid freeze-thaw cycles.
SourceE. coli.
Purity> 97%, as determined by SDS-PAGE and visualized by silver stain. Endotoxin: < 1.0 EU per 1ug of the protein as determined by the LAL method.
FormSupplied as a lyophilized powder in 10 mM MES, 50 mM sodium sulfate, 0.2 mM EDTA and
0.2 mM DTT, pH 6.5. Reconstitute with PBS to a concentration of 0.1mg/ml.
Important NoteThis product as supplied is intended for research use only, not for use in human, therapeutic or diagnostic applications without the expressed written authorization of United States Biological.

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