FLUORESCENT DERIVATIVES OF THROMBOXANE B2 - SYNTHESIS, SPECTROSCOPIC AND IMMUNOLOGICAL PROPERTIES

Thromboxane B2 has been labeled by four fluorescent probes structurall y related to coumarin (4-bromomethyl-7-methoxycoumarin, 7-[(chlorocarb onyl) methoxy]-4-methylcoumarin, 4-luminarin) or anthracen (panacyl br omide). The purity of the derivatives determined by liquid chromatogra phy was over 90%. The extinction coefficient, Stokes' shift, quantum y ield, life-time and the anisotropy of the emitted fluorescence were de termined. Immunorecognition of thromboxane B2 derivatives was checked by competition immunoassays. Among the derivatives tested, that obtain ed with 4-luminarin has a suitable Stokes' shift (95 nm), a quantum yi eld of 0.46, a single value of excited state life-time (9.3 nsec), a w ell-preserved immunorecognition and a good chemical stability. Prelimi nary results in competition experiments showed variations in fluoresce nce anisotropy correlated to thromboxane B2 concentration.