Human Interferon-alpha 2b (Recombinant)

Recombinant Human Interferon-alpha 2b (IFN-a)

Source: E. coli

Background: At least 23 different variants of IFN-alpha are known. The individual proteins have molecular masses between 19-26 kDa and consist of proteins with lengths of 156-166 and 172 amino acids. All IFN-alpha subtypes possess a common conserved sequence region between amino acid positions 115-151 while the amino-terminal ends are variable. Many IFN-alpha subtypes differ in their sequences at only one or two positions. Naturally occurring variants also include proteins truncated by 10 amino acids at the carboxy-terminal end.

Description: Recombinant Human Interferon-alpha 2b produced in E. coli is a single, non-glycosylated, polypeptide chain containing 165 amino acids and having a molecular mass of 19269 Dalton. The Interferon-alpha 2b gene was obtained from human leukocytes. IFN-alpha 2b is purified by proprietary chromatographic techniques.

Physical Appearance: Sterile Filtered White lyophilized (freeze-dried) powder.

Formulation: Lyophilized from a (1mg/ml) solution in containing 2.3mg Sodium phosphate dibasic and 0.55mg sodium phosphate monobasic buffer.

Solubility: It is recommended to reconstitute the lyophilized IFN-alpha 2b in sterile 18MO-cm H₂O not less than 100 µg/ml, which can then be further diluted to other aqueous solutions.

Stability: Lyophilized Interferon-alpha 2b although stable at room temperature for 3 weeks, should be stored desiccated below -18°C. Upon reconstitution Interferon-alpha 2b should be stored at 4 C between 2-7 days and for future use below -18°C. For long term storage it is recommended to add a carrier protein (0.1% HSA or BSA). Please avoid freeze-thaw cycles.

Purity: Greater than 98.0% as determined by: (a) Analysis by RP-HPLC. (b) Anion-exchange FPLC. (c) Analysis by reducing and non-reducing SDS-PAGE Silver Stained.

Amino acid sequence: The sequence of the first five N-terminal amino acids was determined and was found to be Met-Cys-Asp-Leu-Pro. N-terminal methionine has been completely removed enzymatically.

Dimers and aggregates: Less than 1% as determined by silver-stained SDS-PAGE gel analysis.

Biological Activity: IFN-alpha 2b is fully biologically active when compared to WHO standard. The specific activity as determined in a viral resistance assay using bovine kidney MDBK cells was found to be 2.6 x 10⁸ IU/ mg.

Endotoxin: Less than 0.1 ng/ g (IEU/ g) of Recombinant Interferon-alpha 2b.

Protein content: Protein quantitation was carried out by two independent methods: 1. UV spectroscopy at 280 nm using the absorbency value of 0.924 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 Recombinant Interferon-alpha 2b as a Reference Standard.

Usage: BioWORLD's products are furnished for LABORATORY RESEARCH USE ONLY. The product may not be used as drugs, agricultural or pesticidal products, food additives or household chemicals.