Activatable fluorescent probes for hydrolase enzymes based on coumarin-hemicyanine hybrid fluorophores with large Stokes shifts

We show that the equilibrium of intramolecular spirocyclization of coumarin-hemicyanine hybrid fluorophores can be finely tuned by means of chemical modifications. We used this scaffold to develop activatable fluorescent probes with large Stokes shifts for gamma-glutamyltranspeptidase and esterase.