Nonnatural Reactivity of Cofactor-Dependent Enzymes upon Light Irradiation
Accessing Non-Natural Reactivity by Irradiating Nicotinamide-Dependent Enzymes with Light.
15 February 2017 (online)
Key wordsketoreductase - photoexcitation - nicotinamide-dependent enzymes - debromination - lactones
An asymmetric light-mediated reductive debromination of racemic α-bromolactones is reported by the Hyster group. The combination of a ketoreductase derived from either Lactobacillus kefiri (LKADH) or Ralstonia (RasADH), NADP+, and blue LED light furnished the desired lactones in high yields (≤91%) and good to excellent enantioselectivities (er ≤ 98:2).
A great challenge in biocatalysis is the discovery and development of novel reaction pathways and catalytic functions. The authors demonstrate that a nicotinamide-dependent ketoreductase can change its natural function from carbonyl reduction to that of a radical initiator and chiral source of hydrogen, simply by irradiation of the cofactor with light. This strategy leads to novel and selective radical-mediated reactions.