Defluorination of 4-fluorophenol by cytochrome P450BM3-F87G: activation by long chain fatty aldehydes

Abstract

Cytochrome P450(BM3)-F87G catalyzed the oxidative defluorination of 4-fluorophenol, followed by reduction of the resulting benzoquinone to hydroquinone via the NADPH P450-reductase activity of the enzyme. The k (cat) and K (m) for this reaction were 71 ± 5 min(-1) and 9.5 ± 1.3 mM, respectively. Co-incubation of the reaction mixture with long chain aldehydes stimulated the defluorination reaction, with the 2,3-unsaturated aldehyde, 2-decenal producing a 12-fold increase in catalytic efficiency. At 150 μM aldehyde, k (cat) increased to 158 ± 4, while K (m) decreased to 1.8 ± 0.2. The effects of catalase, glutathione and ascorbate on the reaction were all consistent with a direct oxygen insertion mechanism, as opposed to a radical mechanism. The study demonstrates the potential use of P450(BM3) mutants in oxidative defluorination reactions, and characterizes the novel stimulatory action of straight chain aldehydes on this activity.

Discovery of a P450-Catalyzed Oxidative Defluorination Mechanism toward Chiral Organofluorines: Uncovering a Hidden Pathway

“…Cytochrome P450 monooxygenases are ubiquitous and versatile biocatalysts found in nature, − which partake in the metabolism of various endogenous and exogenous compounds such as drugs, environmental pollutants, and carcinogens. − Relevant to our present study is the finding that P450s are capable of catalyzing the oxidative defluorination of certain fluoroalkanes, − fluoro-aromatics − and even fluorine-containing macromolecular drugs. − Although varieties of oxidative defluorination procedures catalyzed by P450 have been reported, mechanistic studies have focused mainly on the defluorination of fluorinated aromatic compounds, as reported in pioneering studies. ,− ,, P450-catalyzed oxidative defluorination of fluorinated aromatics involves an electrophilic attack of Fe IV O (Cpd I) on the substrate, the formation and rearrangement of a transient cationic intermediate, and the generation of quinone and fluoride ion release as final Fe–O bond cleavage occurs (Scheme a). In the presence of a reducing agent, the quinone can be further reduced to phenolic products such as hydroquinone.…”

Selective Ortho‐Hydroxylation–Defluorination of 2‐Fluorophenolates with a Bis(μ‐oxo)dicopper(III) Species

“…[7] The oxidative dehalogenation of 4fluorophenols has also been reported for cytochrome P450 and chloroperoxidase. [8] Tyrosinase is a ubiquitous dicopper enzyme that catalyzes the ortho-hydroxylation of phenols to catechols and the subsequent oxidation to quinones using dioxygen as oxidant, [9] in an overall reaction analogous to that taking place in FAD-dependent phenol hydroxylases. [7] Tyrosinase operates via a (h 2 :h 2 -peroxo)dicopper(II) species (P), that undergoes electrophilic attack over the arene.…”

Toward the development of a molecular toolkit for the microbial remediation of per-and polyfluoroalkyl substances

“…P450 2E1 from human livers exhibited oxidative defluorination activity on fluorinated inhalation anesthetics (e.g., sevoflurane, isoflurane, and methoxyflurane), resulting in the generation of toxic metabolic intermediates ( 116 , 117 ). Furthermore, P450 BM3 -F87G, a mutant form of P450 BM3 from Bacillus megaterium , catalyzed the oxidative defluorination of 4-fluorophenol to benzoquinone that was further reduced to hydroquinone through the NADPH P450-reductase ( 118 ) ( Fig. 4 ).…”