Multitasking Enzyme

Enzyme-catalyzed reactions are a significant part of the toolkit chemists use to generate chiral building blocks with high purity. Despina J. Bougioukou and Jon D. Stewart at the University of Florida now report an enzyme that facilitates two different reaction pathways depending on the configuration of the starting material (J. Am. Chem. Soc., DOI: 10.1021/ja800200r). Their findings could lead to a wider variety of optically pure precursors for materials or pharmaceuticals. The multitasking enzyme, a dehydrogenase, catalyzes the reduction of electron-poor double bonds with the help of an NADPH cofactor. Typically, this type of enzyme adds a pair of hydrogens either to the same face or to opposite faces of the substrate's double bond. Stewart's team used an isotope-labeled cofactor to demonstrate that their enzyme can do both. More specifically, the enzyme reduced the R- and S-enantiomers of perillaldehyde (shown) to the same product (red), a result that has not been possible with other reductase enzymes in the past.