Effect of ricin on biosynthesis of myeloma protein (IgA) and general cellular proteins in MOPC-315 cells.

Ricin, a phyto-toxin from the seeds of Ricinus communis, preferentially inhibits synthesis of myeloma protein by MOPC-315 cells as compared to the synthesis of general proteins. In contrast, cycloheximide inhibited equally both myeloma protein synthesis as well as general protein synthesis. These results suggest that proteins synthesized near or on cell membranes are more sensitive to Ricin which binds to the acceptor molecule on the plasma membrane.