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Asymmetric alkene reduction by yeast old yellow enzymes and by a novel Zymomonas mobilis reductase

2007; Wiley; Volume: 98; Issue: 1 Linguagem: Inglês

10.1002/bit.21415

1097-0290

André C. Müller, Bernhard Hauer, Bettina Rosche,

Amino Acid Enzymes and Metabolism

Abstract The genes encoding yeast old yellow enzymes (OYE 1, 2, and 3) and NAD(P)H‐dependent 2‐cyclohexen‐1‐one reductase from Zymomonas mobilis (NCR) were expressed separately in Escherichia coli . All four recombinant strains reduced the carbon double bond in α,β‐unsaturated alkenals and alkenones, however rates and enantio‐specificities differed. Which of the two possible enantiomers was predominantly formed, was not only dependent on the choice of enzyme but also on the substrate: In addition to a dependency on methylation in α‐ or β‐position, the data of this study illustrate that firstly the E ‐ or Z ‐configuration ( cis ‐ or trans ‐) of the carbon double‐bond and secondly the remainder of the substrate molecule play roles in determining enantio‐specificity. Based on the currently accepted mechanism of flavin mediated anti ‐hydrogenation of the carbon double bond, the data in this study may be explained by a flipped orientation of some of the substrates in the active center of OYE. Biotechnol. Bioeng. 2007; 98: 22–29. © 2007 Wiley Periodicals, Inc.