Interleukin 13 (IL-13) is a protein that in humans is encoded by the IL13 gene. IL-13 was first cloned in 1993 and is located on chromosome 5q31 with a length of 1.4kb. It has a mass of 13 kDa and folds into 4 alpha helical bundles. The secondary structural features of IL-13 are similar to that of Interleukin 4 (IL-4); however it only has 25% sequence homology to IL-4 and is capable of IL-4 independent signaling. IL-13 is a cytokine secreted by T helper type 2 (Th2) cells, CD4 cells, Natural killer T cell, Mast cell, Basophil cells, Eosinophil cells and Nuocyte cells. Interleukin-13 is a central regulator in IgE synthesis, goblet cell hyperplasia, mucus hypersecretion, airway hyperresponsiveness, fibrosis and chitinase up-regulation. It is a mediator of allergic inflammation and different diseases including asthma.

Sequence: 
MSAPFSFLSNVKYNFMRIIKYEFILNDALNQSIIRANDQYLTAAALHNLDEAVKFDMGAYKSSKDDAKITVILRISKTQLYVTAQDEDQPVLLK
EMPEIPKTITGSETNLLFFWETHGTKNYFTSVAHPNLFIATKQDYWVCLAGGPPSITDFQILENQA with polyhistidine tag at the
C-terminus

Source:
Escherichia coli

Endotoxin level:
<0.01 EU per 1 μg of the protein by the LAL method. Activity:
Measure by its ability to induce TF-1 cells proliferation. The ED₅₀ for this effect is<0.8 ng/mL. The specific activity of recombinant human IL-13 is approximately >1 x10⁶ IU/mg.

Purity:
>95% as determined by SDS-PAGE. Ni-NTA chromatography

Formulation:
The protein was lyophilized from a solution containing 1X PBS, pH 8.0.

Reconstitution:
It is recommended to reconstitute the lyophilized protein in sterile H₂O to a concentration not less than 100 μg/mL and incubate the stock solution for at least 20 min to ensure sufficient re-dissolved.

Storage:
Lyophilized protein should be stored at -20°C.
Upon reconstitution, protein aliquots should be stored at -20°C or -80°C.

Note:
Please use within two weeks after protein reconstitution.

Data Sheet