1999 Fiscal Year Final Research Report Summary
Development and application of degradation system for polychlorinated dioxin
| Project/Area Number |
10558103
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
Functional biochemistry
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
ESAKI Nobuyoshi Institute for Chemical Research, Kyoto University Professor, 化学研究所, 教授 (50135597)
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| Co-Investigator(Kenkyū-buntansha) |
KITABATAKE Senji Research Center, Unitika Ltd. Department Head, 中央研究所, 部長
YOSHIMURA Tohru Institute for Chemical Research, Kyoto University Associate Professor, 化学研究所, 助教授 (70182821)
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| Project Period (FY) |
1998 – 1999
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| Keywords | chlorinared organic compound / fluorinated organic compound / chloropropionate / fluoroacetate / dehalogenase |
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| Research Abstract |
We isolated a fluoroacetate-degrading bacterium from soil, and purified fluoroacetate dehalogenase, which catalyzes the hydrolytic dehalogenation of fluoroacetate, from this bacterium. The enzyme also acted on chloroacetate and bromoacetate, but did not catalyzed the hydrolysis of haloalkanoic acids whose carbon chain lengths are longer than three. We also carried out screening using a medium containing 2-chloropropionate as a carbon source, and isolated a bacterium degrading this substrate from lake water. The enzyme isolated from this bacterium, DL-2-haloacid dehalogenase, catalyzed the hydrolysis of both D-and L-2-chloropropionates. The enzyme acted on various haloacetates as well as 2-chloropropionamide. The gene encoding this enzyme was cloned, and its nucleotide sequence was determined. The gene product was estimated to be composed of 301 amino acid residues, and its molecular weight was calculated to be 34,049. We analyzed the reaction mechanism of DL-2-haloacid dehalogenase. When the single-turnover enzyme reaction was carried out using 2-chloropropionate as a substrate in the presence of HィイD22ィエD2ィイD118ィエD1O, ィイD118ィエD1O was found to be incorporated into the product, lactate. The enzyme was not labeled with ィイD118ィエD1O even after the multiple-turnover enzyme reaction in the presence of HィイD22ィエD2ィイD118ィエD1O. These results indicate that the water molecule activated by the enzyme directly attacks the substrate to displace the halogen atom.
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Research Products
(8 results)
