Effect of phalloidin on actin proteolysis as measured by viscometry and fluorimetry

Abstract
Even at low concentration, phalloidin [an Amanita sp. toxic heptapeptide] shows a marked protection of rabbit F-actin against the action of trypsin or pronase. G-actin is not protected at any concentration of phalloidin. The kinetics of the proteolysis show that a change in the environment of tryptophan residues is preceded by disruption of the filamentous structure of F-actin.