Alcaligenes eutrophus JMP134 "2,4-dichlorophenoxyacetate monooxygenase" is an alpha-ketoglutarate-dependent dioxygenase.
The Alcaligenes eutrophus JMP134 tfdA gene, encoding the enzyme responsible for the first step in 2,4-dichlorophenoxyacetic acid (2,4-D) biodegradation, was overexpressed in Escherichia coli, and several enzymatic properties of the partially purified gene product were examined. Although the tfdA-encoded enzyme is typically referred to as 2,4-D monooxygenase, we were unable to observe any reductant-dependent activity. Rather, we demonstrate that this enzyme is a ferrous ion-dependent dioxygenase that uses alpha-ketoglutarate as a cosubstrate. The alpha-ketoglutarate is converted to succinate concomitant with 2,4-D conversion to 2,4-dichlorophenol. By using [1-14C]alpha-ketoglutarate, we established that carbon dioxide is the second product derived from alpha-ketoglutarate. Finally, we verified the proposal that glyoxylate is the second product derived from 2,4-D.
Fukumori
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Center for Microbial Ecology, Michigan State University, East Lansing 48824.
Hausinger
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D015084:2,4-Dichlorophenoxyacetic Acid / Q000378:metabolism*; D000421:Alcaligenes / Q000201:enzymology* / Q000235:genetics; D001426:Bacterial Proteins / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D002245:Carbon Dioxide / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics; D007656:Ketoglutaric Acids / Q000378:metabolism / Q000494:pharmacology*; D010105:Oxygenases / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D011994:Recombinant Proteins / Q000096:biosynthesis; D013386:Succinates / Q000032:analysis
D001426:Bacterial Proteins; D007656:Ketoglutaric Acids; D011994:Recombinant Proteins; D013386:Succinates; D002245:Carbon Dioxide; D015084:2,4-Dichlorophenoxyacetic Acid; D010105:Oxygenases