Comparison of serum protein inhibitors from various mammals, chicken and silkworms against four proteases.

1. Protein serum inhibitors against four proteases were compared using eight mammals, chicken and silkworms. 2. The similarity of inhibition spectra and electrophoretograms was found in related mammals. 3. In the silkworm and chicken, inhibitory activities against fungal protease and subtilisin were extremely high. 4. Electrophoretic patterns of inhibitors for chymotrypsin and trypsin were very similar in mammals, but different in the silkworm, that is, mammalian inhibitors seemed to show broader protease specificity. 5. Electrophoretic bands of the silkworm inhibitors showed more dispersed molecular species than those of other animals. 6. Column chromatographic patterns of silkworm inhibitors against four proteases showed more diverse and distinct profiles than those of other animals.