Synonyms
FGF21; FGF-21; fibroblast growth factor 21
Description
Fibroblast growth factor 21 (FGF-21) is a member of the FGF gene family. Based on its structure, FGF-21 is further classified into a subfamily of FGFs along with FGF-19 and -23. At the amino acid sequence level, mature rat FGF-21 is 92% identical to mouse FGF-21. In comparison to other FGF subfamilies, a heparin-binding domain is uniquely absent in FGF-19 subfamily members. Lack of this domain confers endocrine function to FGF-19 members and enables them to freely diffuse within tissues and accumulate in the circulatory system. The biological activity of FGF-21 requires binding to Klotho beta, a co-receptor that is in complex with cell surface FGF receptors (FGF R). Binding of FGF-21 to Klotho beta facilitates FGF R activation and autophosphorylation resulting in the initiation of multiple downstream signaling cascades. FGF-21 cannot independently bind to FGF Rs, thus its effects are restricted to target tissues that express Klotho beta. FGF-21 functions as a physiological regulator of cellular metabolism, including glucose uptake in adipocytes and cellular sensitivity to insulin. FGF-21 is basally expressed in the pancreas, thymus, and liver, as well as in adipose tissue. Local and systemic metabolic stress has been shown to induce expression of FGF-21 in the liver, muscles, and fat. Modulation of FGF-21 expression is associated with a number of metabolic disorders, including obesity and diabetes.
Molecular Weight
Approximately 19.7 kDa.
AA sequence
AYPISDSSPL LQFGGQVRQR YLYTDDDQDT EAHLEIREDG TVVGTAHRSP ESLLELKALK PGVIQILGVK ASRFLCQQPD GTLYGSPHFD PEACSFRELL LKDGYNVYQS EAHGLPLRLP QKDSQDPATR GPVRFLPMPG LPHEPQEQPG VLPPEPPDVG SSDPLSMVEP LQGRSPSYAS
Appearance
Sterile Filtered White lyophilized (freeze-dried) powder.
Purity
> 95% by SDS-PAGE and HPLC analyses.
Biological Activity
The ED50 as determined by thymidine uptake assay using FGF-receptors transfected BaF3 cells is less than 0.5 μg/mL, corresponding to a specific activity of > 2.0 × 103 IU/mg in the presence of 5 µg/mL of rMuKlotho-β and 10 μg/mL of heparin. Fully biologically active when compared to standard.
Endotoxin
< 1.0 EU per 1μg of the protein by the LAL method.
Formulation
Lyophilized from a 0.2 µm filtered concentrated solution in PBS, 500 mM NaCl, pH 7.4.
Reconstitution
We recommend that this vial be briefly centrifuged prior to opening to bring the contents to the bottom. Reconstitute in sterile distilled water or aqueous buffer containing 0.1% BSA to a concentration of 0.1-1.0 mg/mL. Stock solutions should be apportioned into working aliquots and stored at ≤ -20°C. Further dilutions should be made in appropriate buffered solutions.