Tumor Necrosis Factor alpha, Recombinant, Rat (TNFa)
|Molecular Biology||Storage: -20°CShipping: Blue Ice|
TNF is secreted by macrophages, monocytes, neutrophils, T-cells, NK-cells following their stimulation by bacterial LPS . Cells expressing CD4 secrete TNF-alpha while CD8 cells secrete little or no TNF-alpha. The synthesis of TNF-alpha is induced by many different stimuli including interferons, IL2 , GM-CSF.
Recombinant rat TNF-alpha produced in E.Coli is a single, non-glycosylated, polypeptide chain containing 157 amino acids and having a molecular mass of 17339.44 Dalton. Recombinant Rat TNF-alpha is purified by standard chromatographic techniques.
Amino Acid Sequence:
The sequence of the first five N-terminal amino acids was determined and was found to be Met-Leu-Arg-Ser-Ser.
Dimers and Aggregates:
Less than 1% as determined by silver-stained SDS-PAGE gel analysis.
Rat TNF-alpha is fully biologically active when compared to standard. The ED50 as determined by the cytolysis of murine L929 cells in the presence of Actinomycin D is < 0.05ng/ml, corresponding to a Specific Activity of 5x107 IU/mg.
0.1ng/ug (IEU/ug) of Rat TNF-alpha.
Protein quantitation was carried out by two independent methods:
1. UV spectroscopy at 280 nm using the absorbency value of 1.25 as the extinction coefficient for a 0.1% (1mg/ml) solution. This value is calculated by the PC GENE computer analysis program of protein sequences (IntelliGenetics).
2. Analysis by RP-HPLC, using a calibrated solution of TNF-a as a Reference Standard.
It is recommended to reconstitute the lyophilized Rat TNF-alpha in sterile 18M -cm H2O not less than 100µg/ml, which can then be further diluted to other aqueous solutions.
Lyophilized Rat TNF-alpha although stable at room temperature for 3 weeks, should be stored desiccated below -180C. Upon reconstitution Rat TNF-alpha should be stored at 40C between 2-7 days and for future use below -180C. For long term storage it is recommended to add a carrier protein (0.1% HSA or BSA). Please prevent freeze-thaw cycles.
Source: E. coli
Purity: 97% as determined by:
(a) Analysis by RP-HPLC.
(b) Anion-exchange FPLC.
(c) Analysis by reducing and non-reducing SDS-PAGE Silver Stained gel.
Concentration: As reported
Form: Supplied as a lyophilized powder without additives.
Important Note: This product as supplied is intended for research use only, not for use in human, therapeutic or diagnostic applications without the expressed written authorization of United States Biological.