PURPOSE: A Pegylated interferon alpha isomer is provided to improve specific activity and persistence in a human body. CONSTITUTION: A polymer of human interferone alpha enables PEG binding at a specific site by modification of an amino acid sequence. The amino acid modification includes the addition of a proline-cysteine or cyste amino acid sequence at the C-terminus. The size of the PEG is 20 kDa to 40 kDa.
