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Protein film voltammetry of Rhodobacter capsulatus xanthine dehydrogenase.
J Am Chem Soc. 2003 Dec 17; 125(50):15352-8.JA

Abstract

Xanthine dehydrogenase (XDH) from the bacterium Rhodobacter capsulatus catalyzes the hydroxylation of xanthine to uric acid with NAD(+) as the electron acceptor. R. capsulatus XDH forms an (alphabeta)(2) heterotetramer and is highly homologous to homodimeric eukaryotic XDHs. The crystal structures of bovine XDH and R. capsulatus XDH showed that the two proteins have highly similar folds; however, R.capsulatus XDH is at least 5 times more active than bovine XDH and, unlike mammalian XDH, does not undergo the conversion to the oxidase form. Here we demonstrate electrocatalytic activity of the recombinant enzyme, expressed in Escherichia coli, while immobilized on an edge plane pyrolytic graphite working electrode. Furthermore, we have determined all redox potentials of the four cofactors (Mo(VI/V), Mo(V/IV), FAD/FADH, FADH/FADH(2) and two distinct [2Fe-2S](2+/+) clusters) using a combination of potentiometric and voltammetric methods. A novel feature identified in catalytic voltammetry of XDH concerns the potential for the onset of catalysis (ca. 400 mV), which is at least 600 mV more positive than that of the highest potential cofactor. This unusual observation is explained on the basis of a pterin-associated oxidative switch during voltammetry that precedes catalysis.

Authors+Show Affiliations

Centre for Metals in Biology, Department of Chemistry, University of Queensland, Brisbane 4072, Australia.No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

14664579

Citation

Aguey-Zinsou, Kondo François, et al. "Protein Film Voltammetry of Rhodobacter Capsulatus Xanthine Dehydrogenase." Journal of the American Chemical Society, vol. 125, no. 50, 2003, pp. 15352-8.
Aguey-Zinsou KF, Bernhardt PV, Leimkühler S. Protein film voltammetry of Rhodobacter capsulatus xanthine dehydrogenase. J Am Chem Soc. 2003;125(50):15352-8.
Aguey-Zinsou, K. F., Bernhardt, P. V., & Leimkühler, S. (2003). Protein film voltammetry of Rhodobacter capsulatus xanthine dehydrogenase. Journal of the American Chemical Society, 125(50), 15352-8.
Aguey-Zinsou KF, Bernhardt PV, Leimkühler S. Protein Film Voltammetry of Rhodobacter Capsulatus Xanthine Dehydrogenase. J Am Chem Soc. 2003 Dec 17;125(50):15352-8. PubMed PMID: 14664579.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Protein film voltammetry of Rhodobacter capsulatus xanthine dehydrogenase. AU - Aguey-Zinsou,Kondo François, AU - Bernhardt,Paul V, AU - Leimkühler,Silke, PY - 2003/12/11/pubmed PY - 2004/2/27/medline PY - 2003/12/11/entrez SP - 15352 EP - 8 JF - Journal of the American Chemical Society JO - J Am Chem Soc VL - 125 IS - 50 N2 - Xanthine dehydrogenase (XDH) from the bacterium Rhodobacter capsulatus catalyzes the hydroxylation of xanthine to uric acid with NAD(+) as the electron acceptor. R. capsulatus XDH forms an (alphabeta)(2) heterotetramer and is highly homologous to homodimeric eukaryotic XDHs. The crystal structures of bovine XDH and R. capsulatus XDH showed that the two proteins have highly similar folds; however, R.capsulatus XDH is at least 5 times more active than bovine XDH and, unlike mammalian XDH, does not undergo the conversion to the oxidase form. Here we demonstrate electrocatalytic activity of the recombinant enzyme, expressed in Escherichia coli, while immobilized on an edge plane pyrolytic graphite working electrode. Furthermore, we have determined all redox potentials of the four cofactors (Mo(VI/V), Mo(V/IV), FAD/FADH, FADH/FADH(2) and two distinct [2Fe-2S](2+/+) clusters) using a combination of potentiometric and voltammetric methods. A novel feature identified in catalytic voltammetry of XDH concerns the potential for the onset of catalysis (ca. 400 mV), which is at least 600 mV more positive than that of the highest potential cofactor. This unusual observation is explained on the basis of a pterin-associated oxidative switch during voltammetry that precedes catalysis. SN - 0002-7863 UR - https://www.unboundmedicine.com/medline/citation/14664579/Protein_film_voltammetry_of_Rhodobacter_capsulatus_xanthine_dehydrogenase_ L2 - https://doi.org/10.1021/ja037940e DB - PRIME DP - Unbound Medicine ER -