Recombinant Human Tumor Necrosis Factor α
Tumor Necrosis Factor-Alpha (TNF-a), also known as cachectin, is named after its activity to cause tumor necrosis in vivo when injected into tumor-bearing mice. TNF-a is expressed as a 26 kDa membrane bound protein and is then cleaved by TNF-a converting enzyme (TACE) to release the soluble 17 kDa monomer which forms homotrimers in circulation. Recombinant TNF-a exists as homo-dimer, -trimer or -pentamer. TNF-a is believed to play roles in antitumor activity, immune modulation, inflammation, anorexia, cachexia, septic shock, viral replication and ematopoiesis. TNF-a is expressed in many types of cells but primarily in macrophage cells in response to immunological challenges such as bacteria (lipopolysaccharides), viruses, parasites, mitogens and other cytokines. TNF-a is closely related to the 25 kDa protein Tumor Necrosis Factor-b (beta) (lymphotoxin) with 28% amino acid sequence identity, sharing the same receptors (TNFR1 and TNFR2) and cellular actions. TNF-a causes cytolysis or cytostasis of many transformed cells, being synergistic with (gamma) r-interferon in its cytotoxicity. Although it has little effect on many cultured normal human cells, TNF-a appears to be directly toxic to vascular endothelial cells. Other actions of TNF-a include stimulating growth of human fibroblasts and other cell lines, activating polymorphonuclear neutrophils and osteoclasts, and induction of interleukin-1, prostaglandin E2 and collagenase production. Although TNF-a is currently being evaluated in treatment of certain cancers and AIDS-related symptoms, the recombinant TNFa offered is for research only.
Other Sizes
| BX1100-20: | 20 ug |
| BX1100-200: | 200 ug |
| BX1100-1000: | 1 mg |
Custom size is also available upon request.
Specifications
| CAS Number: | 94948591 |
| MDL number: | MFCD00148692 |
| Lot number: | On label |
| Formulation: | Lyophilized powder lyophilized from a volatile buffer (50 mM NH4HCO3 , pH 8.0). |
| Preservative: | None |
| Molecular Weight: | 17 kD |
| Purity: | >97% on 15% SDS-PAGE |
| Source: | Recombinant mature protein expressed in E. coli (189aa) |
| Sterility: | 0.2 um membrane filtered and packaged aseptically |
| ED50: | 0.01-0.1 ng/ml |
| Endotoxin: | ≤0.1 EU/ug protein |
| QC test: | SDS-PAGE, Native PAGE, ELISA, Cytolysis, TC |
Note: Endotoxin Unit (EU) is determined by Limulus Amebocyte Lysate (LAL) assay.
Cytolysis Assay
The ED50 is defined as the effective concentration of TNF-a that causes 50% cytolysis of murine L929B cells, a TNF-a sensitive mouse fibrosarcoma cell line, in the presence of actinomycin-D. Results may vary depending on cell line used. (Havell, E.A., 1987).
Reconstitution and use
Reconstitute the contents of the vial using sterile phosphate-buffered saline (PBS) to a concentration no less than 100 ug/ml and aliquot for future use. (If the initial rehydration is too diluting, activity may be lost due to the non-specific adsorption to the container). The solution can then be further diluted to a working stock solution. Bovine serum albumin can be added to the working solution to protect TNF-a from loss at low concentrations.
If the product is going to be used for applications requiring absolute asepsis (e.g. cell culture), it's best to filter-sterilize the solution using a sterile and non-pyrogenic 0.2um membrane before use.
Storage and stability
Upon receiving, store the product at -20oC. After reconstitution, store the working aliquots at 2-8oC for no more than 3 months. For extended storage, aliquot the rehydrated solution (≥100 ug/ml) and freeze at -70oC or -20oC. Avoid repeated freezing and thawing. More dilute solutions stored at -20oC will lose activity faster.
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