Chiral Enzymatic Activity in Cell Cultures of Taxus Species

Abstract

Plant cell suspension cultures of <em>Taxus brevifolia</em> and <em>Taxus globosa</em> were used as biocatalysts on an exogenous racemic substrate in order to determine the influence of several parameters on its configurational deracemization bioactivity. <em>Taxus brevifolia</em> demonstrated a directly proportional relationship between the enantiomeric ratio (er) [1] and the time of reaction, yielding a mixture of 90(<em>S</em>):10(<em>R</em>) after 7 days. Pure enantiomers were tested and the results showed that the (<em>S</em>)-enantiomer remained intact, whereas the (<em>R</em>)-enantiomer was biotransformed. The buffer solution did not present any effect. Sucrose and temperature modified the reaction time and the er. The pH was a critical variable in relation to the age of the suspension cultures. <em>Taxus globosa</em> showed a low efficiency for distinguishing between the enantiomers.