Used as a fluorescent probe in biochemical and cellular studies to label and track amine-reactive sites in proteins and other biomolecules. Its fluorescence properties make it valuable for detecting transglutaminase activity, especially in assays involving protein crosslinking. Commonly applied in research to visualize enzyme distribution in tissues and cells under fluorescence microscopy. Also utilized in studying cell permeability and uptake mechanisms due to its ability to penetrate membranes and bind intracellular targets.