Inactivation of porcine kidney betaine aldehyde dehydrogenase by hydrogen peroxide

Jesús A. Rosas-Rodríguez, Elisa M. Valenzuela-Soto

Research output: Contribution to journalArticlepeer-review

9 Scopus citations

Abstract

Concentrated urine formation in the kidney is accompanied by conditions that favor the accumulation of reactive oxygen species (ROS). Under hyperosmotic conditions, medulla cells accumulate glycine betaine, which is an osmolyte synthesized by betaine aldehyde dehydrogenase (BADH, EC 1.2.1.8). All BADHs identified to date have a highly reactive cysteine residue at the active site, and this cysteine is susceptible to oxidation by hydrogen peroxide. Porcine kidney BADH incubated with H2O2(0-500 μM) lost 25% of its activity. However, pkBADH inactivation by hydrogen peroxide was limited, even after 120 min of incubation. The presence of coenzyme NAD+(10-50 μM) increased the extent of inactivation (60%) at 120 min of reaction, but the ligands betaine aldehyde (50 and 500 μM) and glycine betaine (100 mM) did not change the rate or extent of inactivation as compared to the reaction without ligand. 2-Mercaptoethanol and dithiothreitol, but not reduced glutathione, were able to restore enzyme activity. Mass spectrometry analysis of hydrogen peroxide inactivated BADH revealed oxidation of M278, M243, M241 and H335 in the absence and oxidation of M94, M327 and M278 in the presence of NAD+. Molecular modeling of BADH revealed that the oxidized methionine and histidine residues are near the NAD+binding site. In the presence of the coenzyme, these oxidized residues are proximal to the betaine aldehyde binding site. None of the oxidized amino acid residues participates directly in catalysis. We suggest that pkBADH inactivation by hydrogen peroxide occurs via disulfide bond formation between vicinal catalytic cysteines (C288 and C289). © 2011 Elsevier Ireland Ltd.
Original languageAmerican English
Pages (from-to)159-164
Number of pages6
JournalChemico-Biological Interactions
Volume191
Issue number1-3
DOIs
StatePublished - 30 May 2011
Externally publishedYes
EventChemico-Biological Interactions -
Duration: 30 May 2011 → …

Bibliographical note

Funding Information:
Travel to JAAR was supported by USPHS NIH grant R13-AA019612 to present the results of this study at the 15th International Meeting on Enzymology and Molecular Biology of Carbonyl Metabolism in Lexington, KY USA. This study was supported by the Consejo Nacional de Ciencia y Tecnología (CONACYT). JARR received a graduate scholarship from CONACYT.

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