Pushing the bounds of biocatalysis

Abstract

Enzymes often elicit envy from organic chemists. Highly evolved by nature, these biocatalysts can carry out reactions with a selectivity that surpasses most synthetic catalysts. Yet they tend to act on such a narrow range of substrates that chemists haven’t been able to exploit their abilities in a general way. In an effort to broaden enzymes’ reach, researchers led by Alison Narayan at the University of Michigan explored how three known enzymes—called TropB, AzaH, and SorbC—carry out the same reaction (Nat. Chem. 2017, DOI:10.1038/nchem.2879). In the reaction, known as an oxidative dearomatization, a catalyst breaks the aromaticity of a planar ring system to install an oxygen species, forming a valuable chiral building block. Narayan and her team determined which of the three enzymes worked best with which substrates from a group, allowing them to maximize the reaction’s enantioselectivity and site selectivity and enabling the chemists to target specific positions and