High-temperature electrocatalysis using thermophilic P450 CYP119: dehalogenation of CCl4 to CH4.
The use of a thermophilic cytochrome P450, CYP119, in electrocatalytic dehalogenations of C1 halocarbon solvents is studied. Temperature stable enzyme-modified electrodes were constructed using sol-gel and polymeric surfactant approaches. CYP119 deposited in a dimethyldidodecylammonium poly(p-styrene sulfonate) (DDAPSS) film has good retention of electrochemical activity up to 80 degrees C. At potentials approaching the FeII/I couple, the CYP119/DDAPSS films demonstrate high catalytic dehalogenations of the C1 chloromethanes CCl4, CHCl3, and CH2Cl2. Product analysis identified mixtures of sequentially dechlorinated products up to methane; no evidence for radical-coupled products was observed. The yield of methane from the CYP119-catalyzed reduction of CCl4 is increased 35-fold from 25 degrees C to 55 degrees C. In combination with the lack of C2 products, the facility of an overall eight-electron reductive dehalogenation suggests that the substrate is constrained within the protein during electrocatalytic turnover.
Blair
Emek
E
Department of Chemistry, University of California, Irvine, California 92697-2025, USA.
Greaves
John
J
Farmer
Patrick J
PJ
D019843:Archaeal Proteins; D001673:Biodegradation, Environmental; D002251:Carbon Tetrachloride / Q000737:chemistry*; D002384:Catalysis; D003577:Cytochrome P-450 Enzyme System / Q000737:chemistry*; D004563:Electrochemistry / Q000379:methods*; D008697:Methane / Q000737:chemistry*; D010084:Oxidation-Reduction; D010105:Oxygenases / Q000737:chemistry*; D013696:Temperature
D019843:Archaeal Proteins; D003577:Cytochrome P-450 Enzyme System; D002251:Carbon Tetrachloride; D010105:Oxygenases; C408874:CYP119 protein, Sulfolobus solfataricus; D008697:Methane