PMID:7578233
| Citation |
Sun, ZY, Dowd, SR, Felix, C, Hyde, JS and Ho, C (1995) Stopped-flow kinetic and biophysical studies of membrane-associated D-lactate dehydrogenase of Escherichia coli. Biochim. Biophys. Acta 1252:269-77 |
|---|---|
| Abstract |
The enzyme kinetics of the FAD-containing membrane-associated D-lactate dehydrogenase (D-LDH) of Escherichia coli have been investigated by stopped-flow spectroscopy. The reduction of D-LDH by the substrate, D-lactate, exhibits a two-stage behavior as observed by the absorbance change for the enzyme-bound FAD. The fast stage with a maximum rate of 400 s-1 represents the rapid formation of the enzyme-substrate complex and the formation of the equilibrium between the oxidized and the reduced enzyme-substrate complexes. The slow stage, which occurs on the order of 0.36 s-1, represents the slow release of the product, pyruvate, from the reduced enzyme. The formation of a D-LDH semiquinone radical was not observed during the oxidation of D-lactate by D-LDH at 25 degrees C. However, during the subsequent electron transfer from the reduced enzyme to a nitroxide spin-label, a one-electron acceptor, an enzyme intermediate has been observed and identified by both optical and EPR spectroscopies as an anionic semiquinone. Results from 1H-NMR spectroscopic studies suggest the possible formation of a substrate carbanion when D-lactate is bound at the active site of D-LDH. |
| Links | |
| Keywords |
2,6-Dichloroindophenol; Bacterial Outer Membrane Proteins/chemistry; Bacterial Outer Membrane Proteins/metabolism; Benzoquinones/chemistry; Electron Spin Resonance Spectroscopy; Escherichia coli/enzymology; Kinetics; L-Lactate Dehydrogenase/chemistry; L-Lactate Dehydrogenase/metabolism; Lactates/metabolism; Lactic Acid; Magnetic Resonance Spectroscopy; Oxidation-Reduction; Spectrophotometry; Spin Labels |
| edit table |
Significance
You can help EcoliWiki by summarizing why this paper is useful
Useful Materials and Methods
You can help Ecoliwiki by describing the useful materials (strains, plasmids, antibodies, etc) described in this paper.
Annotations
<protect><annotationlinks/></protect>
EcoliWiki Links
Add links to pages that link here (e.g. gene, product, method pages)
See also
References
See Help:References for how to manage references in EcoliWiki.
