Dansyl cadaverine is the most popular fluorescent transglutaminase substrate to label proteins by transaminidation. It has also been used to prepare other small fluorescent biomolecules via amidation or reductive amination. It should be noted that the Dansyl fluorescence is highly environment-sensitive.
Ray E and Samanta AK (1996). Dansyl cadaverine regulates ligand induced endocytosis of interleukin-8 receptor in human polymorphonuclear neutrophils. FEBS Lett 378, 235-9; Pincus JH, et al. (1975). Dansyl cadaverine: a fluorescent probe and marker in cell membrane studies. Arch Biochem Biophys 169, 724-30.