Effects of plant ribosome-inactivating proteins on ribosomes from Musca domestica.

1. Ribosomes from M. domestica larvae were isolated and their susceptibility to the action of several ribosome-inactivating proteins (RIPs) from plants was tested. 2. Ribosome-inactivating proteins inhibited, to different extents, phenylalanine polymerization by ribosomes. 3. Analysis of RNA from RIP-treated ribosomes showed the appearance of an aniline-cleavable rRNA fragment resulting from the N-glycosidase activity of the RIPs. 4. The release of adenine from saporin 6-treated M. domestica ribosomes was demonstrated by h.p.l.c. analysis.