Potent catalytic inactivator of eukaryotic protein synthesis. It may be a component of natural defense mechanisms involved in protecting the kernel against soil-borne fungal infections. Endohydrolysis of the N-glycosidic bond at one specific adenosine on the 28S rRNA. Synthesized and stored in the kernel as a 34 kDa inactive precursor. During germination, this neutral precursor is converted into a basic, active form by limited proteolysis, which removes 25 AA of net charge -6 from the center of the polypeptide chain. Additional processing also occurs at the N- and C-termini of the polypeptide. A two-chain active RIP (comprised of 16.5 and 8.5 kDa fragments that remain tightly associated) is produced from this processing event. Belongs to the ribosome-inactivating protein family. Type 1 RIP subfamily.