Product 7032

Propidium Iodide is a cell-impermeant, red-fluorescent dye that is commonly used for staining the nucleus of dead cells and as a counterstain for chromosomes. Because Propidium Iodide does not passively cross the cell membranes of most viable cells, it is commonly used as a red-fluorescent stain for dead cells in a culture. Propidium Iodide is an intercalating dye that binds to both DNA and RNA without significant preference for nucleic acid sequences and with a stoichiometry of about one dye for every 4–5 base pairs. The fluorescence of Propidium Iodide is greatly enhanced upon binding to nucleic acids and the DNA bound form is excited near 535 nm with a fluorescence emission near 617 nm. Nucleases may be used to distinguish DNA staining from RNA staining. We offer Propidium Iodide as standard purity (Product 7032) and high purity (Product 6995) solids as well as convenient, ready-to-use solutions in water (Products 6996, 7930). .