Description: Recombinant Human IFN-alpha 2a produced in E. coli is a single, non-glycosylated, polypeptide chain containing 165 amino acids and having a molecular mass of 19241 Dalton. Pegylated IFN-alpha 2a is manufactured by attaching a 20KD mPEG to the primary amino acid of IFN-alfa 2a. Quality Control: Biological activity: Pegylated IFN-alfa 2a is fully biologically active when compared to standard. The specific activity as determined in a viral resistance assay using bovine kidney MDBK cells was found to be 5 x 107 IU/mg.