Live-or-Dye™ Fixable Viability Staining Kits are cell membrane impermeable amine-reactive dyes designed for discrimination between live and dead cells during flow cytometry. The dyes are able to enter into dead cells that have compromised membrane integrity and covalently label free amines on intracellular proteins. The dye labeling is extremely stable, allowing the cells to be fixed and permeabilized without loss of fluorescence or dye transfer between cells. The Live-or-Dye™ staining protocol has been optimized to maximize live/dead discrimination with minimal live cell staining, in order to prevent interference with immunostaining. Live-or-Dye™ Fixable Viability Stains are dead cell specific in all cell types, including mammalian cells, bacteria and yeast. Live-or-Dye™ 750/777 is suitable for excitation by 633 nm or 640 nm laser line. This trial size kit has sufficient reagent for 50 assays.