PMID:8706750

Citation	Tedeschi, G, Negri, A, Mortarino, M, Ceciliani, F, Simonic, T, Faotto, L and Ronchi, S (1996) L-aspartate oxidase from Escherichia coli. II. Interaction with C4 dicarboxylic acids and identification of a novel L-aspartate: fumarate oxidoreductase activity. Eur. J. Biochem. 239:427-33
Abstract	L-Aspartate oxidase is a monomeric flavoprotein that catalyzes the first step in the de novo biosynthetic pathway for pyridine nucleotide formation under both aerobic and anaerobic conditions. In spite of the physiological importance of this biosynthesis in particular in facultative aerobic organisms, such as Escherichia coli, little is known about the electron acceptor of reduced L-aspartate oxidase in the absence of oxygen. In this report, evidence is presented which suggests that in vitro fumarate can play such a role. L-Aspartate oxidase binds succinate and fumarate with Kd values of 0.24 mM and 0.22 mM, respectively. A competitive behaviour was observed for these two dicarboxylic acids towards iminoaspartate and sulfite ions. Photoreduction experiments suggest that fumarate and succinate bind at or close to the active site of the molecule. A new fumarate reductase activity of L-aspartate oxidase is reported using benzylviologen or L-aspartate as reductants and fumarate as oxidant. Steady-state kinetics for the oxidase and the fumarate reductase activity of L-aspartate oxidase were obtained using either fumarate or oxygen as electron acceptor and L-aspartate as electron donor. Finally, succinate was identified as the product of the L-aspartate:fumarate oxidoreductase activity using radiolabeled fumarate under anaerobic conditions. The results suggest that fumarate can be a valuable alternative to oxygen as a substrate for L-aspartate oxidase.
Links	PubMed
Keywords	Amino Acid Oxidoreductases/chemistry; Amino Acid Oxidoreductases/metabolism; Cloning, Molecular; Dicarboxylic Acids/metabolism; Electron Transport; Escherichia coli/enzymology; Kinetics; Mathematics; Oxidation-Reduction; Recombinant Proteins/chemistry; Recombinant Proteins/metabolism; Spectrophotometry; Substrate Specificity; Sulfites
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
ECOLI:NADB	enables	GO:0044318: L-aspartate:fumarate oxidoreductase activity	ECO:0000314: direct assay evidence used in manual assertion		F		Seeded From UniProt	complete

References

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