Paclitaxel fluorescent derivatives

The problem was overcome with the use of mildly fixed microtubules [10] in which the paclitaxel binding site is unaltered, while protected from cold and dilution depolymerisation and a paclitaxel molecule bound to a fluorescent probe (either fluorescein or difluorofluorescein) [8], The fluorescent derivatives of paclitaxel were then tested to check that they compete with taxoids for the same site, with the same 1 1 stoichiometry producing the same celular effects as paclitaxel and docetaxel, thus it can be assumed that they bind for the same site [9], Using these stabilized microtubules, it is possible to determine precisely the binding constant of the fluorescent taxoid which was found to be of the order of 108 M at 25°C. 

Han Y, Chaudhary AG, Chordia MD, Sacked DL, Perez-Ramirez B, Kingston DGI, Bane S (1996) Interaction of a Fluorescent Derivative of Paclitaxel (Taxol) with Microtubules and Tubulin-Colchicine. Biochemistry 35 14173... 

Fig. 2 Left cytoplasmic microtubules in interphase kidney epithelial cells imaged with the fluorescent paclitaxel derivative Flutax-2 (green) and nuclear DNA stained with Hoescht 33342 (blue). Right mitotic spindle from a dividing metaphase cell with similarly imaged microtubules and chromosomes. Bars indicate 10 pm (micrographs courtesy of Isabel Barasoain)...

Li Y, Edsall J, R, Jagtap PG, Kingston DGI, Bane S (2000) Equilibrium Studies of a Fluorescent Paclitaxel Derivative Binding to Microtubules. Biochemistry 39 616... 

Baloglu E, Kingston DGI, Patel P, Chatterjee SK, Bane SL (2001) Synthesis and Microtubule Binding of Fluorescent Paclitaxel Derivatives. Bioorg Med Chem Lett 11 2249... 

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