Document Detail

Reversible inactivation of dihydrolipoamide dehydrogenase by mitochondrial hydrogen peroxide.
MedLine Citation:
PMID:  23205777     Owner:  NLM     Status:  MEDLINE    
Under oxidative stress conditions, mitochondria are the major site for cellular production of reactive oxygen species (ROS) such as superoxide anion and H2O2 that can attack numerous mitochondrial proteins including dihydrolipoamide dehydrogenase (DLDH). While DLDH is known to be vulnerable to oxidative inactivation, the mechanisms have not been clearly elucidated. The present study was therefore designed to investigate the mechanisms of DLDH oxidative inactivation by mitochondrial reactive oxygen species (ROS). Mitochondria, isolated from rat brain, were incubated with mitochondrial respiratory substrates such as pyruvate/malate or succinate in the presence of electron transport chain inhibitors such as rotenone or antimycin A. This is followed by enzyme activity assay and gel-based proteomic analysis. The present study also examined whether ROS-induced DLDH oxidative inactivation could be reversed by reducing reagents such as DTT, cysteine, and glutathione. Results show that DLDH could only be inactivated by complex III- but not complex I-derived ROS; and the accompanying loss of activity due to the inactivation could be restored by cysteine and glutathione, indicating that DLDH oxidative inactivation by complex III-derived ROS was a reversible process. Further studies using catalase indicate that it was H2O2 instead of superoxide anion that was responsible for DLDH inactivation. Moreover, using sulfenic acid-specific labeling techniques in conjunction with two-dimensional Western blot analysis, we show that protein sulfenic acid formation (also known as sulfenation) was associated with the loss of DLDH enzymatic activity observed under our experimental conditions. Additionally, such oxidative modification was shown to be associated with preventing DLDH from further inactivation by the thiol-reactive reagent N-ethylmaleimide. Taken together, the present study provides insights into the mechanisms of DLDH oxidative inactivation by mitochondrial H2O2.
Liang-Jun Yan; Nathalie Sumien; Nopporn Thangthaeng; Michael J Forster
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2012-12-12
Journal Detail:
Title:  Free radical research     Volume:  47     ISSN:  1029-2470     ISO Abbreviation:  Free Radic. Res.     Publication Date:  2013 Feb 
Date Detail:
Created Date:  2013-01-10     Completed Date:  2013-06-25     Revised Date:  2014-03-19    
Medline Journal Info:
Nlm Unique ID:  9423872     Medline TA:  Free Radic Res     Country:  England    
Other Details:
Languages:  eng     Pagination:  123-33     Citation Subset:  IM    
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MeSH Terms
Antimycin A / pharmacology
Brain / metabolism
Catalase / metabolism
Cysteine / pharmacology
Dihydrolipoamide Dehydrogenase / antagonists & inhibitors,  metabolism*
Dithiothreitol / pharmacology
Electron Transport Complex I / metabolism
Electron Transport Complex III / metabolism
Ethylmaleimide / chemistry,  metabolism
Glutathione / pharmacology
Hydrogen Peroxide / metabolism*
Malates / chemistry
Mitochondria / metabolism*
Oxidation-Reduction / drug effects
Oxidative Stress / drug effects*
Pyruvic Acid / chemistry
Rats, Sprague-Dawley
Rotenone / pharmacology
Succinic Acid / chemistry
Superoxides / metabolism
Grant Support
Reg. No./Substance:
0/Malates; 03L9OT429T/Rotenone; 11062-77-4/Superoxides; 642-15-9/Antimycin A; 6915-15-7/malic acid; 8558G7RUTR/Pyruvic Acid; AB6MNQ6J6L/Succinic Acid; BBX060AN9V/Hydrogen Peroxide; EC Transport Complex III; EC; EC Transport Complex I; EC Dehydrogenase; GAN16C9B8O/Glutathione; K848JZ4886/Cysteine; O3C74ACM9V/Ethylmaleimide; T8ID5YZU6Y/Dithiothreitol

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