Production of ribosome-inactivating protein from hairy root cultures of Luffa cylindrica (L.) Roem.

Transformed root lines of Luffa cylindrica (L.) Roem. (Cucurbitaceae) were established by inoculation of in vitro grown plantlets with wild type Agrobacterium rhizogenes strain 1855. Cloned lines of hairy roots were tested for the presence of ribosome-inactivating proteins; crude extracts inhibited protein synthesis in a reaction mixture based on rabbit reticulocyte lysate. Inhibitory activity increased during culture period, reaching a maximum value in the stationary phase. No activity could be detected in the culture medium, nor in extracts from callus and/or suspension cultures. A ribosome-inactivating protein having specific activity of 62,100 U mg protein(-1) and a molecular mass of 26-28,000 Da was purified to homogeneity. The protein showed N-glycosidase activity on rat liver ribosomes. The results demonstrate that hairy root cultures can be successfully utilized for the in vitro production of ribosome-inactivating proteins.