5-Maleimido-eosin

5-maleimido-eosin is a good photosensitizer and can be used to selectively label thiols. It has a quantum yield of 0.57 for singlet oxygen generation, which makes it useful for photoconversion of electron-rich materials such as diaminobenzidine (DAB).

5-maleimido-eosin is also used as triplet probe used for the measurment of rotational diffusion of protein in solution and in membranes, includin myosin and pyruvate dehydrogenase.

References:
M.J. King et al.: British J. Haematol. 124(1), 106 (2004)
E. Majima al.: Biochim. Biophys. Acta, 1243(3), 336 (1995)
S. Ishiwata et al.: J. biol. Chem.262, 8314 (1987)
A.J.W.G. Visser et al.: Eur. J. Biochem. 121, 233 (1981).