Biologic activity in a fragment of recombinant human interferon alpha.

To attempt to locate functionally important regions of the interferon (IFN) molecule, recombinant human IFN-alpha 2 was subjected to proteolytic digestion. The bacterial proteinase thermolysin produced two major complementary fragments, HuIFN-alpha 2-(1-110) and HuIFN-alpha 2-(111-153). After reduction with 2-mercaptoethanol and separation of the two major fragments on NaDodSO4/polyacrylamide gel electrophoresis, antiviral activity persisted in the larger, Mr 12,000, fragment consisting of the amino-terminal 110 amino acids.