At least 23 different variants of Interferon-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 carboxyl-terminal end.

·Description
Recombinant HSA fusion Interferon alpha-2b produced in P. Pichia is a single, non-glycosylated, polypeptide chain having a molecular mass of 85.7 kDa.

·Quality Control
Biological Activity: The specific activity as determined in a viral resistance assay using VSV-WISH cells was found to be 5.0 x 106 IU/mg.
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 gel.
Endotoxin: Less than 0.1 ng/µg (IEU/µg) of HSA-IFN-alpha 2b.

·Formulation
Lyophilized from a (3mg/ml) solution in containing 2.4mg Tris base and 8.8mg sodium chloride.

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

·Storage
Lyophilized HSA-IFN alpha-2b although stable at room temperature for 3 weeks, should be stored desiccated below -18oC. Upon reconstitution HSA-IFN alpha-2b should be stored at 4oC between 2-7 days and for future use below -18oC. For long-term storage it is recommended to add a carrier protein (0.1% HSA or BSA).

Please avoid freeze-thaw cycles.