GF®568 - Phalloidin 標記鬼筆環肽
貨號：JXF40131-50T
規格：50T
價格：800元
Product Description
Phalloidin is a bicyclic peptide that belongs to a family of toxins isolated from the deadly Amanita phalloides mushroom.
Fluorescent phalloidins bind F-actin with nanomolar affinity and are water soluble, thus providing convenient probes
for labeling, identifying, and quantifying F-actin in cryopreserved tissue sections, cell cultures, or cell-free experiments.
Phalloidin contains an unusual thioether bridge between cysteine and tryptophan residues that forms an inner ring structure.
At elevated pH, this thioether is cleaved and the toxin loses its affinity for actin. Fluorescently labeled phalloidins stain F-actin
at nanomolar concentrations. Labeled phalloidins have similar affinity for both large and small filaments, binding in a
stoichiometric ratio of about one phalloidin molecule per actin subunit in muscle and non-muscle cells from various species
of plants and animals. Different from antibodies, the binding affinity of phalloidin does not change significantly with actin
among different species. Non-specific staining is negligible, and the contrast between stained and unstained areas is
extremely large. Phalloidin shifts the monomer/polymer equilibrium toward the polymer, lowering the critical concentration
for polymerization up to 30-fold. Phallotoxins also stabilize F-actin, inhibiting depolymerization by cytochalasin,
potassium iodide and elevated temperatures. Because the phalloidin conjugates are small, with an approximate diameter
of 12-15? and molecular weight of <2000 Daltons, a variety of actin-binding proteins including myosin, tropomyosin and
troponin can still bind to actin after treatment with phalloidin. Even more significantly, phalloidin-labeled actin filaments
remain functional; labeled glycerinated muscle fibers still contract, and labeled actin filaments still move on solid-phase
myosin substrates. Fluorescent phalloidin can also be used to quantify the amount of F-actin in cells.
