Abstract
A novel enzymatic reaction involved in the metabolism of aliphatic epoxides by Xanthobacter strain Py2 is described. Cell extracts catalyzed the CO2-dependent carboxylation of propylene oxide (epoxypropane) to form acetoacetate and beta-hydroxybutyrate. The time courses of acetoacetate and beta-hydroxybutyrate formaton indicate that acetoacetate is the primary product of propylene oxide carboxylation and that beta-hydroxybutyrate is a secondary product formed by the reduction of acetoacetate. Analogous C5 carboxylation products were identified with 1,2-epoxybutane as the substrate. In the absence of CO2, propylene oxide and 1,2-epoxybutane were isomerized to form acetone and methyl ethyl ketone, respectively, as dead-end products. The carboxylation of short-chain epoxides to beta-keto acids is proposed to serve as the physiological reaction for the metabolism of aliphatic epoxides in Xanthobacter strain Py2.
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- Ehrenberg L., Hussain S. Genetic toxicity of some important epoxides. Mutat Res. 1981 Jan;86(1):1–113. doi: 10.1016/0165-1110(81)90034-8. [DOI] [PubMed] [Google Scholar]
- Hartmans S., Smits J. P., van der Werf M. J., Volkering F., de Bont J. A. Metabolism of Styrene Oxide and 2-Phenylethanol in the Styrene-Degrading Xanthobacter Strain 124X. Appl Environ Microbiol. 1989 Nov;55(11):2850–2855. doi: 10.1128/aem.55.11.2850-2855.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hartmans S., de Bont J. A., Harder W. Microbial metabolism of short-chain unsaturated hydrocarbons. FEMS Microbiol Rev. 1989 Sep;5(3):235–264. doi: 10.1016/0168-6445(89)90034-x. [DOI] [PubMed] [Google Scholar]
- Jacobs M. H., Van den Wijngaard A. J., Pentenga M., Janssen D. B. Characterization of the epoxide hydrolase from an epichlorohydrin-degrading Pseudomonas sp. Eur J Biochem. 1991 Dec 18;202(3):1217–1222. doi: 10.1111/j.1432-1033.1991.tb16493.x. [DOI] [PubMed] [Google Scholar]
- LAW J. H., SLEPECKY R. A. Assay of poly-beta-hydroxybutyric acid. J Bacteriol. 1961 Jul;82:33–36. doi: 10.1128/jb.82.1.33-36.1961. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Small F. J., Ensign S. A. Carbon dioxide fixation in the metabolism of propylene and propylene oxide by Xanthobacter strain Py2. J Bacteriol. 1995 Nov;177(21):6170–6175. doi: 10.1128/jb.177.21.6170-6175.1995. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Small F. J., Tilley J. K., Ensign S. A. Characterization of a new pathway for epichlorohydrin degradation by whole cells of xanthobacter strain py2. Appl Environ Microbiol. 1995 Apr;61(4):1507–1513. doi: 10.1128/aem.61.4.1507-1513.1995. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wade D. R., Airy S. C., Sinsheimer J. E. Mutagenicity of aliphatic epoxides. Mutat Res. 1978 Nov;58(2-3):217–223. doi: 10.1016/0165-1218(78)90012-5. [DOI] [PubMed] [Google Scholar]