The product is an interferon beta-1a to which a single, linear 20,000 dalton (Da) methoxy poly(ethyleneglycol)-O-2-methylpropionaldehyde (PEG) molecule is covalently attached to the alpha amino group of the N-terminal amino acid residue. The amino acid sequence of the recombinant interferon beta-1a is identical to that of the human interferon beta counterpart. Interferon beta-1a https://www.creativebiomart.net/therapeutic-proteins/p/23/interferon-beta-1a/