At least 23 different variants of Interferon-alpha are known. The individual proteins have molecular masses between 19,000-26,000 Da 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. GenScript Human Serum Albumin and Interferon (HSA-IFN)-alpha 2b produced in P. Pichia is a single non-glicosylated, polypeptide chain having a molecular mass of 85,700 Da. Synonym: HSA-IFN-alpha 2b, HSA-IFNa2b, HSA-IFN a2. Formulation: Lyophilized from a (1 mg/ml) solution in containing 5.55 mg sodium phosphate dibasic, 5.55 mg sodium phosphate monobasic buffer, 296 mg sucrose and 0.37 mg Tween 80.