Differential ricin sensitivity of rat liver and wheat germ ribosomes in polyuridylic acid translation

Daniel B. Cawley, Mary L. Hedblom, Eugene J. Hoffman, L. L. Houston

Research output: Contribution to journalArticlepeer-review

20 Scopus citations


Rat liver and wheat germ ribosomes were treated with ricin or ricin A chain and assayed for polyuridylic acid-directed protein synthesis. Ricin A chain was not able to inhibit polyphenylalanine synthesis by wheat germ ribosomes at 5000 times the concentration that was effective in preventing synthesis by rat liver ribosomes. Wheat germ S-100 did not prevent inactivation of rat liver ribosomes by ricin and the presence of rat liver S-100 did not cause wheat germ ribosomes to become sensitive to ricin. Ricintreated and control 40 and 60 S ribosomal subunits from wheat germ and rat liver were mixed in all possible combinations and assayed for protein synthesis activity. The only inhibited ribosome was that containing a ricin-treated 60 S subunit from rat liver. The binding of ricin A chain to wheat germ ribosomes was compared to that observed with rat liver ribosomes. Gel filtration of the ricin A chain-ribosome complex on agarose confirmed results obtained by sedimentation and showed that rat liver and wheat germ ribosomes bind ricin A chain in a similar manner. Escherichia coli ribosomes bound very small amounts of ricin A chain compared to rat liver and wheat germ ribosomes. These results indicate that binding alone is not sufficient to result in ribosome inactivation.

Original languageEnglish (US)
Pages (from-to)690-695
Number of pages6
JournalArchives of Biochemistry and Biophysics
Issue number2
StatePublished - Aug 1977
Externally publishedYes

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology


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