Chiral Enzymatic Activity in Cell Cultures of Taxus Species

Plant cell suspension cultures of Taxus brevifolia and Taxus globosa were used as biocatalysts on an exogenous racemic substrate in order to determine the influence of several parameters on its con- figurational deracemization bioactivity. Taxus brevifolia demonstrated a directly proportional relationship between the enantiomeric ratio (er) (1) and the time of reaction, yielding a mixture of 90(S):10(R) after 7 days. Pure enantiomers were tested and the results showed that the (S)-enantiomer remained intact, whereas the (R)-enantiomer was bio- transformed. 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. Taxus globosa showed a low efficiency for distinguishing between