Recombinant Chicken Protein IL-18, 25µg
- Predicted molecular weight: 19.5 kDa
- No endotoxins, TAGS, and carrier-free
- Naturally folded and post-translationally modified
IBI recombinant proteins are expressed in Pichia pastoris (yeast) system which provides many advantages over E. coli systems. Yeast systems promote proper protein folding and post-translational modifications for greater bio-activity. The recombinant proteins are endotoxin free and are purified without HIS-TAGS or any other TAG. IBI’s yeast expression system has proven to produce more active proteins that more closely resemble their host form.
Interleukin-18 (IL-18) is a cytokine produced by macrophages and other cells that belongs to the IL-1 superfamily. IL-18 works together with IL-12 to induce cell-mediated immunity following infection with microbial products like lipopolysaccharide (LPS). After stimulation with IL-18, natural killer (NK) cells and certain T cells release another important cytokine called interferon-gamma (IFN-gamma) or type II interferon that plays an important role in activating the macrophages or other cells. Apart from its physiological role, IL-18 is also able to induce severe inflammatory reactions, which suggests its role in certain inflammatory disorders. The protein encoded by this gene is a proinflammatory cytokine. This cytokine can induce the IFN-gamma production of T cells. The combination of this cytokine and IL-12 has been shown to inhibit IL-4 dependent IgE and IgG1 production, and enhance IgG2a production of B cells.
The recombinant chicken protein IL-18 has a predicted molecular weight of 19.5 kDa.
All IBI recombinant proteins are lyophilized and shipped at room temperature without carrier protein. Proteins can be reconstituted in sterile PBS with at least 0.1% of carrier protein such as BSA or cell assay media.
The IL-18 chicken protein can be used in cell culture, as an IL-18 ELISA Standard, and as a Western Blot Control.
Country of Origin: USA
Formulation/Reconstitution: Lyophilized, Reconstitute with sterile phosphate-buffered saline containing at least 0.1% carrier protein.
Molecular Weight: 19.5 kDa (calculated)
Purity: >95% (as visualized by SDS-PAGE analysis)
Purification: Ion-exchange chromatography
Entrez Gene ID: 395312
Amino Acid Sequence: AFCKDKTIKR FFRNVNSQLL VVRPDLNVAA FEDVTDQEVK SGSGMYFDIH CYKTTAPSAG MPVAFSVQVE DKSYYMCCEK EHGKMVVRFR EGEVPKDIPG ESNIIFFKKT FTSCSSKAFK FEYSLEQGMF LAFEEEDSLR KLILKKLPRE DEVDETTKFV TSHNERHNL (169)
How do I reconstitute the recombinant protein?--Most of the recombinant proteins can be reconstituted in sterile phosphate-buffered saline with 0.1% carrier protein, which is most commonly Bovine Serum Albumin (BSA) --Recombinant bovine proteins cannot be reconstituted in BSA because BSA could cause a reaction in cell cultures. In the case of bovine proteins, Equine Serum Albumin can be used. --If protein vial is left unopened, it can be stored at room temperature or -20C for up to 12 months. --Once protein is open and reconstituted, it must be stored at -20°C and is viable for up to 3 months. --Avoid repeated freeze/thaw cycles as this could cause denaturation of proteins.
What is the activity of the recombinant protein?--IBI recombinant proteins are sold in units of micrograms (µg) --The recombinant protein is quantified using the BCA Assay which favors the customer in terms of amount of protein. The BCA assay is not perfect, but at least it is standard for all proteins. --If the activity exists, it will be on the Data Sheet shipped with the product --Activity cannot be determined for the animal recombinant proteins because an assay does not exist. (Only human proteins have an assay to determine activity --If end-user wants to know the activity, they can do an activity titer for each lot they use. This is useful because there can be significant differences in activity from lot to lot. --If customer is concerned, they can buy multiple bottles and store them. Also, we can let customer know if we have a good supply of the lot number they are purchasing if they are going to purchase again in the future.
Can we provide custom proteins?--We can only make published proteins with a known DNA sequence. --There is a lead time of 6 months for the process from start to finish to be completed. Contact IBI if interested in using custom proteins.
If IBI does not stock the protein I need, what options do I have?IBI may carry a protein that is homologous to the recombinant protein of interest. Because of homology between animals, proteins in a more complicated system are able to cause the same reaction in less complicated systems. For example, chicken proteins can work for amphibian applications.
Why did my protein arrive in multiple vials?Some proteins are more soluble than others. The proteins that are more difficult to purify can be packaged in multiple vials, so the end-user receives the correct quantity they ordered. Also, lyophilization process works best with volumes of 100 µg or less.