title: Protection of actin from heat denaturation by various phallotoxins.
abstract: Phallotoxins protect F-actin from heat denaturation at a temperature of 70 degrees C for 3 min. This has been shown by difference spectroscopy. G-actin is not protected from heat denaturation by phalloidin. Among the various phallopeptides investigated, 4 toxic ones showed the same protecting ability, whereas non-toxic seco-compounds has no effect. The non-toxic (S)-phalloidinsulfoxide A exhibited only a partial protecting activity, corresponding to an affinity for F-actin of about one tenth of that of the toxic peptides. Evidence for this was obtained from the easy displacement of the sulfoxide A from F-actin by phalloidin as well as by a spectroscopic dilution titration.
mesh_terms: D000199:Actins; D006358:Hot Temperature; D009842:Oligopeptides / Q000494:pharmacology*; D010590:Phalloidine / Q000031:analogs & derivatives / Q000494:pharmacology*; D011489:Protein Denaturation / Q000187:drug effects; D013454:Sulfoxides / Q000494:pharmacology
chemical_list: D000199:Actins; D009842:Oligopeptides; D013454:Sulfoxides; D010590:Phalloidine