Structural relationship between barley (Hordeum vulgare) trypsin inhibitor and castor-bean (Ricinus communis) storage protein.

A significant sequence homology was found between barley (Hordeum vulgare) trypsin inhibitor and castor-bean (Ricinus communis) seed glutamine-rich storage protein. This appears to suggest a divergent evolution of the two different classes of seed proteins and to support a view that plant proteinase inhibitors may also act as storage proteins.