We report here the successful establishment of callus, cell and root c
ultures from explants of in-vitro-grown plantlets of the soapwort Sapo
naria officinalis L. The production of saporin in the different tissue
systems was evaluated by determining the capability of crude extracts
to inactivate protein synthesis and by Western blotting analysis. Pro
tein synthesis inhibition varied in callus and derived cell suspension
s and in cultured roots, the latter, in particular, showing the lowest
specific activity. The ribosome-inactivating principle from root cult
ures was purified to homogeneity by cation exchange chromatography.