ABSTRACT
References .......................................................................................................................... 617
The production of (R)-phenylacetylcarbinol (R-PAC), as a precursor intermediate in
the synthesis of L-ephedrine, was one of the first industrial biotransformations to be
exploited. The reaction is catalyzed by fermenting baker’s yeast, Saccharomyces cerevisiae,
as a side reaction of pyruvate decarboxylase (PDC), a thiamine pyrophosphate (TPP)-linked
a-ketoacid decarboxylases. R-PAC can be produced by chemical synthesis from cyanohydrins, but biotransformation represents the preferred industrial synthesis route. Other
a-ketoacid decarboxylases include benzoylformate decarboxylase, phenylpyruvate decarboxylase, phosphonopyruvate decarboxylase, indole-3-pyruvate decarboxylase, and 3-sulfopyr-
uvate decarboxylase. Bacterial and yeast decarboxylases have been evaluated as biocatalysts
not only for the synthesis of acyloin-type compounds but also for the production of hydroxyl
ketones [1], a-arylacetate [2], D-amino acids [3], dopamine [4], and organic acids [5]. Some
606 Biocatalysis in the Pharmaceutical and Biotechnology Industries
other TPP-dependent enzymes, which are not a-ketoacid decarboxylases, also have potential roles in bioorganic synthesis.
