Evidence for a radical mechanism of the dechlorination of chlorinated propenes mediated by the tetrachloroethene reductive dehalogenase of Sulfurospirillum muftivorans.
The reductive dehalogenation of chlorinated propenes was studied with the tetrachloroethene reductive dehalogenase purified from Sulfurospirillum multivorans to obtain indications for a radical mechanism of this reaction. When reduced methyl viologen (MV), which is a radical cation, was applied as electron donor for the reduction of different chloropropenes, a significant part of MV could not be rereduced with Ti(III) citrate, indicating that a part of the MV was consumed in a side reaction. Mass spectrometric analysis of assays with MV as electron donor revealed the formation of side products, the masses of which might account for the formation of adducts from a chloropropenyl radical and reduced methyl viologen. With Ti(III) citrate as sole electron donor, 2,3-dichloropropene was reduced and as a side product, 2,5-dichloro-1,5-hexadiene was formed demonstrating that the reductive dechlorination of 2,3-dichloropropene proceeds via a radical reaction mechanism. The results support different dehalogenation mechanisms forthe reductive dechlorination of chloropropenes and halogenated ethenes.
Institute for Microbiology, Department of Applied and Ecological Microbiology, Friedrich Schiller University, Philosophenweg 12, D-07743 Jena, Germany. schmitz@sirs-lab.com
Roland P H
RP
Schmitz
Julia
J
Wolf
Andreas
A
Habel
Anke
A
Neumann
Kerstin
K
Ploss
Ales
A
Svatos
Wilhelm
W
Boland
Gabriele
G
Diekert
D000498:Allyl Compounds / Q000737:chemistry*; D002713:Chlorine / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D020565:Epsilonproteobacteria / Q000201:enzymology*; D006843:Hydrocarbons, Chlorinated; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000737:chemistry*; D010269:Paraquat / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D000498:Allyl Compounds; D006843:Hydrocarbons, Chlorinated; C043065:2,3-dichloro-1-propene; D002713:Chlorine; D010088:Oxidoreductases; C112990:tetrachloroethene dehalogenase; D010269:Paraquat