Fluorescent derivatives of thromboxane B(2): Synthesis, spectroscopic and immunologic properties

Thromboxane B(2) has been labeled by four fluorescent probes structurally related to coumarin (4-bromomethyl-7-methoxycoumarin, 7-[(chlorocarbonyl) methoxy]-4-methylcoumarin, 4-luminarin) or anthracen (panacyl bromide). The purity of the derivatives determined by liquid chromatography was over 90%. The extinction coefficient, Stokes' shift, quantum yield, life-time and the anisotropy of the emitted fluorescence were determined. Immunorecognition of thromboxane B(2) derivatives was checked by competition immunoassays. Among the derivatives tested, that obtained with 4-luminarin has a suitable Stokes' shift (95 nm), a quantum yield of 0.46, a single value of excited state life-time (9.3 nsec), a well-preserved immunorecognition and a good chemical stability. Preliminary results in competition experiments showed variations in fluorescence anisotropy correlated to thromboxane B(2) concentration.