unlike previously available methods , based on the separation of rna fragments by gel electrophoresis , the new method allows one to investigate the activity of ricin on ribosomes pretreated with alpha-sarcin , a cytotoxin which cleaves 28s rrna at one nucleotide distance from the site of attack of ricin . alpha-sarcin makes ribosomes a poor substrate for ricin , the release of adenine requiring concentrations of ricin 50-times higher than those effective on untreated ribosomes .
C0035701
rrna
C0035553
ribosomes