$900.00Catalog Number: BX1100-200Size: 200 ug

Human TNFa

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.

Quantity

$900.00

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