Modifications of the hydrophobic character at the 7 and 10 positions of the
taxoids greatly modified the effect of these drugs on the tubulin-microtub
ule system. The presence of an alkyl chain at these positions decreased the
activity while their corresponding more polar analogues restored the activ
ity of these molecules. It appears that the recognition of taxoids by tubul
in depends on the location of the most important hydrophobic area. (C) 2000
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