Fully biologically active when compared to standard. The specific activity determined by an anti-viral assay is no less than 1.0 × 10 8 IU/mg.

IFN-alpha 1b/IFNA13 Protein, Human, Recombinant (A137V) is expressed in E. coli. The accession number is P01562.

Human

E. coli

Interferon-α1b,IFN-α1b

Cys24-Glu189 (Ala137Val)

> 96% as determined by SDS-PAGE; > 96% as determined by HPLC

It is recommended that this vial be briefly centrifuged prior to opening to bring the contents to the bottom. Reconstitute the lyophilized powder in sterile distilled water or aqueous buffer containing 0.1% BSA to a concentration of 0.1-1.0 mg/ml.

Upon receiving, this product remains stable for up to 6 months at -70°C or -20°C. Upon reconstitution, the product should be stable for up to 1 week at 4°C or up to 3 months at -20°C. Avoid repeated freeze-thaw cycles.

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.