Dansylcadaverine is a fluorescent probe. In Vitro: Detection of Dansylcadaverine fluorescence after SDS-PAGE shows that the amount of actin-thymosin β₄ crosslink is very low in the presence of Dansylcadaverine and transglutaminase, while there are large amounts of Dansylcadaverine-labeled thymosin β₄ and actin. The amount of cross-link further decreases in the presence of Dansylcadaverine competing for Lys residues of either G-actin or thymosin β₄ (100 μM). In the absence of thymosin β₄, Dansylcadaverine-labeled actin polymerized to F-actin as revealed by fluorescence detection after native PAGE^[1].