Possesses features of some constitutive defense agent. The coordinate Opaque-2-controlled synthesis of this protein and the major seed storage proteins (zeins) may provide the germinating seedling with both nutritional benefits and protection against pathogen invasion of the surrounding endosperm. Endohydrolysis of the N-glycosidic bond at one specific adenosine on the 28S rRNA. Monomer. Accumulates to high levels in seeds. Belongs to the ribosome-inactivating protein family. Type 1 RIP subfamily.