Oxidation of aliphatic olefins by toluene dioxygenase: enzyme rates and product identification.
Toluene dioxygenase from Pseudomonas putida F1 has been studied extensively with aromatic substrates. The present work examined the toluene dioxygenase-catalyzed oxidation of various halogenated ethenes, propenes, butenes and nonhalogenated cis-2-pentene, an isomeric mix of 2-hexenes, cis-2-heptene, and cis-2-octene as substrates for toluene dioxygenase. Enzyme specific activities were determined for the more water-soluble C2 to C5 compounds and ranged from <4 to 52 nmol per min per mg of protein. Trichloroethene was oxidized at a rate of 33 nmol per min per mg of protein. Products from enzyme reactions were identified by gas chromatography-mass spectrometry. Proton and carbon nuclear magnetic resonance spectroscopy of compounds from whole-cell incubation confirmed the identity of products. Substrates lacking a halogen substituent on sp2 carbon atoms were dioxygenated, while those with halogen and one or more unsubstituted allylic methyl groups were monooxygenated to yield allylic alcohols. 2,3-Dichloro-1-propene, containing both a halogenated double bond and a halogenated allylic methyl group, underwent monooxygenation with allylic rearrangement to yield an isomeric mixture of cis- and trans-2,3-dichloro-2-propene-1-ol.
Lange
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CC
Department of Biochemistry, Biological Process Technology Institute, and Center for Biodegradation Research and Informatics, University of Minnesota, St. Paul 55108, USA.
Wackett
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LP
D000475:Alkenes / Q000378:metabolism*; D010084:Oxidation-Reduction; D010105:Oxygenases / Q000494:pharmacology*
D000475:Alkenes; D010105:Oxygenases; C023172:toluene dioxygenase