Purification and characterization of recombinant mouse interferon-beta.

Recombinant mouse interferon-beta (rMuIFN-beta) produced in Escherichia coli was purified to homogeneity and characterized. The purified protein exhibited a single band of Mr 19,900 on SDS-polyacrylamide gel electrophoresis under both reducing and nonreducing conditions, and also exhibited a single band on native polyacrylamide gel electrophoresis at pH 4.3. The observed molecular weight corresponded to that of the polypeptide moiety of natural MuIFN-beta of Mr 19,700. The amino acid composition and the amino-terminal sequence of the purified rMuIFN-beta were identical to those predicted from cDNA sequence. These results indicate that the purified protein is a nonglycosylated MuIFN-beta, which forms no disulfide-linked dimer and probably exists as a monomeric form.