Alpha-sarcin impairs the N-glycosidase activity of ricin on ribosomes.
In a recently described method the RNA N-glycosidase activity of ricin is measured by h.p.l.c. determination of the adenine released from ribosomes after conversion of the base into its fluorescent 1-N6-etheno derivative [Zamboni et al. (1989) Biochem. J., 259, in press]. 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.
Sperti
S
S
Dipartimento di Patologia sperimentale, Università di Bologna, Italy.
Zamboni
M
M
Brigotti
M
M
Rambelli
F
F
Montanaro
L
L
D000225:Adenine / Q000378:metabolism; D001230:Aspergillus / Q000502:physiology; D002384:Catalysis; D004722:Endoribonucleases; D005656:Fungal Proteins / Q000494:pharmacology*; D006026:Glycoside Hydrolases / Q000037:antagonists & inhibitors*; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology*; D012339:RNA, Ribosomal, 28S / Q000187:drug effects / Q000378:metabolism; D012270:Ribosomes / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism; D012276:Ricin / Q000494:pharmacology*
D005656:Fungal Proteins; D011500:Protein Synthesis Inhibitors; D012339:RNA, Ribosomal, 28S; C014801:alpha-sarcin; D012276:Ricin; D004722:Endoribonucleases; D006026:Glycoside Hydrolases; D000225:Adenine