Fluorescent labeling of proteins with Nile red and 2-methoxy-2,4-diphenyl-3(2H)-furanone: Physicochemical basis and application to the rapid stainingof sodium dodecyl sulfate polyacrylamide gels and Western blots

The fluorescent hydrophobic dye Nile red allows the rapid, sensitive, and g eneral staining of proteins in sodium dodecyl sulfate (SDS)-polyacrylamide gels. Nile red staining does not preclude further electroblotting of protei n bands onto polyvinylidene difluoride (PVDF) membranes. The resulting West ern blot can be stained with the covalent fluorescent dye 2-methoxy-2,4-dip henyl-3(2H)-furanone (MDPF) using a simple procedure. MDPF staining allows further N-terminal microsequencing and immunodetection of specific bands. T his review considers the physicochemical, structural, and analytical studie s that have led to the development of Nile red and MDPF staining methods. T he usefulness of these procedures is discussed in comparison to other curre ntly available fluorescent and nonfluorescent protein detection methods.