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Biocatalytic carboxylation of phenol derivatives: kinetics and thermodynamics of the biological Kolbe–Schmitt synthesis
Author(s) -
Pesci Lorenzo,
Glueck Silvia M.,
Gurikov Pavel,
Smirnova Irina,
Faber Kurt,
Liese Andreas
Publication year - 2015
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/febs.13225
Subject(s) - carboxylation , decarboxylation , chemistry , catalysis , regioselectivity , substrate (aquarium) , kinetics , carboxy lyases , phenol , isoprene , organic chemistry , enzyme , oceanography , physics , polymer , quantum mechanics , copolymer , geology
Microbial decarboxylases, which catalyse the reversible regioselective ortho ‐carboxylation of phenolic derivatives in anaerobic detoxification pathways, have been studied for their reverse carboxylation activities on electron‐rich aromatic substrates. Ortho ‐hydroxybenzoic acids are important building blocks in the chemical and pharmaceutical industries and are currently produced via the Kolbe–Schmitt process, which requires elevated pressures and temperatures (≥ 5 bar, ≥ 100 °C) and often shows incomplete regioselectivities. In order to resolve bottlenecks in view of preparative‐scale applications, we studied the kinetic parameters for 2,6‐dihydroxybenzoic acid decarboxylase from Rhizobium sp. in the carboxylation‐ and decarboxylation‐direction using 1,2‐dihydroxybenzene (catechol) as starting material. The catalytic properties ( K m , V max ) are correlated with the overall thermodynamic equilibrium via the Haldane equation, according to a reversible random bi–uni mechanism. The model was subsequently verified by comparing experimental results with simulations. This study provides insights into the catalytic behaviour of a nonoxidative aromatic decarboxylase and reveals key limitations (e.g. substrate oxidation, CO 2 pressure, enzyme deactivation, low turnover frequency) in view of the employment of this system as a ‘green’ alternative to the Kolbe–Schmitt processes.