Determination of the glycosylation patterns, disulfide linkages, and protein heterogeneities of baculovirus-expressed mouse interleukin-3 by mass spectrometry

The primary structure of mouse interleukin-3 (IL-3) expressed by recombinant baculovirus-infected silkworm (Bombyx mori) larvae was analyzed by subjecting isolated IL-3 derived peptides to liquid secondary ion mass spectrometry. Two species of IL-3 were isolated from the silkworm hemolymph by reverse-phase high-pressure liquid chromatography. The major component has M r 20-22×10 3 as determined by SDS-PAGE