초록
<P>Dynamic change of intracellular nicotinamide cofactor concentrations, the limiting factor for the bioreductions catalyzed by oxidoreductases, was monitored in <I>Escherichia coli</I> cells coexpressing diketoreductase and glucose dehydrogenase. On the basis of an unexpected observation, a relationship between catalytic efficiency and cofactor concentrations was established to optimize the process for the preparation of a chiral diol for statin drugs. Consequently, compared to previous reactions by <I>E. coli</I> cells expressing diketoreductase alone, exogenous addition of cofactors was completely eliminated to yield an increase of substrate concentration by 15-fold. The present strategy could be employed in the biocatalytic processes catalyzed by nicotinamide-dependent oxidoreductases.</P><P><B>Graphic Abstract</B><BR><IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/accacs/2011/accacs.2011.1.issue-12/cs200408y/production/images/medium/cs-2011-00408y_0004.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/cs200408y'>ACS Electronic Supporting Info</A></P>