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Modification of an Enzyme Biocatalyst for the Efficient and Selective Oxidative Demethylation of para ‐Substituted Benzene Derivatives
Author(s) -
Chao Rebecca R.,
Lau Ian C.K.,
De Voss James J.,
Bell Stephen G.
Publication year - 2016
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201600951
Subject(s) - chemistry , moiety , hydroxymethyl , aldehyde , bromide , benzoic acid , biocatalysis , oxidative decarboxylation , amide , medicinal chemistry , organic chemistry , enzyme , stereochemistry , catalysis , reaction mechanism
The bacterial CYP199A4 enzyme is able to oxidise a narrow range of aromatic acids, which includes 4‐methoxybenzoic acid, efficiently. A serine 244 to aspartate variant was identified with enhanced activity for a wide range of para ‐methoxy‐substituted benzenes. Substrates in which the acidic benzoic acid moiety is replaced with a phenol and the amide, aldehyde and bromide analogues were all oxidised with high activity by the S244D mutant (product formation rate >600 nmol nmol CYP −1 min −1 ) with turnover numbers of up to 20 000. If the carboxylate moiety was modified to a nitro, ketone, boronic acid, hydroxymethyl or nitrile group, these substrates were also oxidised at a significantly higher activity by S244D than the wild‐type enzyme. 3,4‐Dimethoxybenzaldehyde was demethylated selectively and oxidatively to 3‐methoxy‐4‐hydroxybenzaldehyde by the S244D mutant 84‐fold more rapidly than with the wild‐type enzyme. CYP199A4 would have applications in the catalytic regioselective oxidative demethylation of suitably substituted benzene substrates under mild conditions and in the presence of more oxidatively sensitive functional groups, such as an aldehyde.