Principle of Assay
Phalloidin belongs to a class of toxins called phallotoxins, which are isolated from the death cap mushroom (Amanita phalloides). It is a bicyclic peptide that binds to F-actin specifically. Therefore, the distribution of F-actin can be very conveniently studied by using a fluorescent dye-labeled phalloidin. Inside the phalloidin, there is an unusual thioether bridge between cysteine and tryptophan, which can form an inner ring structure. When the pH is raised, the thioether is cleaved and the phalloidin loses its affinity for actin. This kit uses a orange fluorescent (Ex/Em=593nm/614nm) phalloidin conjugate selectively bound to F-actins, it has much higher photostability than other the fluorescein-phalloidin conjugates. Phalloidin derivatives are convenient probes for labeling, identifying and quantitating F-actins in formaldehyde-fixed and permeabilized tissue sections, which can stain F-actins in cell cultures or cell-free experiments at nanomolar levels.
