Skip to main content
PMC home page
NIHPA Author Manuscripts logoLink to NIHPA Author Manuscripts
. Author manuscript; available in PMC: 2014 Jul 1.
Published in final edited form as: Mol Cell Neurosci. 2012 Jul 20;55:13–16. doi: 10.1016/j.mcn.2012.07.005

An update on the role of mitochondrial α-ketoglutarate dehydrogenase in oxidative stress

Anatoly A Starkov 1
PMCID: PMC3563721  NIHMSID: NIHMS398621  PMID: 22820180

Abstract

The activity of mitochondrial alpha-ketoglutarate dehydrogenase complex (KGDHC) is severely reduced in human pathologies where oxidative stress is traditionally thought to play an important role, such as familial and sporadic forms of Alzheimer's disease and other age-related neurodegenerative diseases. This minireview is focused on substantial data that were accumulated over the last 2 decades to support the concept that KGDHC can be a primary mitochondrial target of oxidative stress and at the same time a key contributor to it by producing reactive oxygen species. This article is part of a Special Issue entitled ‘Mitochondrial function’.

Keywords: Mitochondria, Oxidative stress, Reactive oxygen species

Introduction

The mitochondrial α-ketoglutarate dehydrogenase complex (KGDHC) catalyzes the reaction

α − ketoglutarate + CoASH + NAD+→succinyl − CoA + CO2 + NADH.

It is located in the matrix of mitochondria where it is tightly associated with the matrix side of the inner membrane (Maas and Bisswanger, 1990). It binds specifically to Complex I of the mitochondrial respiratory chain (Sumegi and Srere, 1984) and may form a part of the tricarboxylic acid cycle (TCA) enzyme supercomplex (Lyubarev and Kurganov, 1989). The KGDHC is composed of multiple copies of three enzymes: α-ketoglutarate dehydrogenase (E1k component, EC 1.2.4.2), dihydrolipoamide succinyltransferase (E2k component, EC 2.3.1.12), and dihydrolipoamide dehydrogenase (E3 component, EC 1.6.4.3). The electrons from E1k reduce the lipoyl groups in E2k. E3 reoxidizes the reduced lipoyl groups ofE2k and transfers the electrons to NAD+, forming NADH. The E1k and E3 components are non-covalently bound to a core formed by E2k components (Sheu and Blass, 1999; Wagenknecht et al., 1983). KGDHC is activated by low concentrations of Ca2+ (10−7−10−5 M) and ADP (∼10−4 M for half-maximum activation) (Lawlis and Roche, 1981; McCormack and Denton, 1979), and it is inhibited by high NADH and its own product, succinyl-CoA (Hamada et al., 1975; Kiselevsky et al., 1990; LaNoue et al., 1983; McMinn and Ottaway, 1977; Wan et al., 1989). The latter is the key substrate for heme biosynthesis and also a substrate for the succinyl-CoA ligase, the only enzyme in brain mitochondria with the substantial capacity for ATP-generating substrate-level phosphorylation. Thus, KGDHC is important for generating ATP in the mitochondria in the absence of oxidative phosphorylation (Chinopoulos et al., 2010). The importance of KGDHC in TCA and overall energy and heme metabolism has had been extensively and repeatedly reviewed elsewhere (e.g., see Gibson et al., 2010); this minireview is focused primarily on the properties of KGDHC as the target of oxidative stress and its E3 component as a source of reactive oxygen species.

Why is studying KGDHC important?

The interest in KGDHC activity in relation to human pathology and specifically brain metabolism stems from the fact that its activity is severely reduced in human pathologies where oxidative stressis traditionally thought to play an important role. The KGDHC activity is reduced by ∼57% in brains of patients with Alzheimer's disease as originally reported by Gibson et al. (1988) and later confirmed by several laboratories (Butterworth and Besnard, 1990; Mastrogiacoma et al., 1996; Mastrogiacomo et al., 1993; Terwel et al., 1998). Decreased KGDHC activities occur in genetic (Gibson et al., 1998) and sporadic (Albers et al., 2000) forms of AD. In early AD-type dementia, the neocortical metabolic abnormalities precede the non-memory cognitive defects (Haxby et al., 1986), thereby suggesting a role for dysregulation of metabolism in etiology of AD. KGDHC activity is also reduced in several other age-related neurodegenerative diseases including Parkinson's (Gibson et al., 2003), Huntington (Klivenyi et al., 2004), Wernicke Korskoff (Butterworth et al., 1993) and progressive supranuclear palsy (Albers et al., 2000; Park et al., 2001).

KGDHC is an easy target of oxidative stress

One of the reasons for this consistent deficiency of KGDHC in neurodegenerative diseases may be that KGDHC appears to be more sensitive to oxidative damage than most other mitochondrial proteins (Tretter and Adam-Vizi, 2000), perhaps due to the large number of sulfhydryl groups and tyrosines that are subject to oxidant modification whereas being critical for KGDHC enzymatic activity. Analysis of the human sequence shows that KGDHC has 37 cysteine residues (E1k has 21, E2k has 6 and E3 has 10); there are also multiple tyrosine residues in KGDHC (31 in E1k, 5 in E2k and 11 in E3). KGDHC is sensitive to oxidants that increase 4-hydroxy-2-nonenal (Humphries and Szweda, 1998) and elevate the protein carbonyl content (Cabiscol et al., 2000). A variety of oxidants inactivate KGDHC, such as H2O2 (Chinopoulos et al., 1999; Gibson et al., 2000; Nulton-Persson et al., 2003; Xu et al., 2001), peroxynitrite (Park et al., 1999), nitric oxide (Park et al., 1999), hydroxynonenal (Humphries et al., 1998), chloroamine (Xu et al., 2001), sodium hypochlorite (Xu et al., 2001), t-butyl hydroperoxide (Rokutan et al., 1987) and acrolein (Pocernich and Butterfield, 2003). Catecholamines enhance E3 inactivation by the copper Fenton system (Correa and Stoppani, 1996). Knockout of SOD2 in mice increases ROS production and inactivates E1k of KGDHC (Hinerfeld et al., 2004). Increases in cellular ROS and diminished KGDHC are seen following inhibition of respiration in microglia (Park et al., 1999) and increased MAO expression (Kumar et al., 2003). KGDHC also interacts with thioredoxin to maintain the mitochondrial sulfur redox (Bunik, 2003; Gourlay et al., 2003). Thioredoxin couples the redox state of the lipoyl groups in E2k to glutathione and peroxiredoxin (Bunik, 2003). The increase in the ratio of dihydrolipoate/lipoate in the E2k component reciprocally diminishes E1k activity by changing its cooperative properties (Bunik et al., 1989, 1990), inactivation (Bunik et al., 1997), production of ROS (Bunik and Sievers, 2002) and reduction of disulfides (Bunik et al., 1995). The thiyl radical of the E2k-bound dihydrolipoate induces the inactivation of E1k by one electron oxidation of the 2-oxo acid dehydrogenase catalytic intermediate. The inactivation prevents the transformation of the 2-oxo acids in the absence of terminal substrate, NAD+ (Bunik and Sievers, 2002). Thioredoxin protects KGDHC from the E1k inactivation. In turn, the activity of thioredoxin and other 'oxins (peroxiredoxins, glutaredoxins, which are important in maintaining other sulfhydryl group-dependent enzyme activity) in mitochondria depends on the supply of reducing equivalents from TCA enzymes tothioredoxin reductase 2 that regenerates the 'oxins (Andreyev et al., 2005). This supply depends on the flux through TCA, which is in some tissues (such as the brain (Sheu and Blass, 1999)) controlled by KGDHC activity. Thus, ample evidence support the concept that KGDHC is an easy target of oxidative stress because it seems to be especially vulnerable to oxidative damage while being crucially important for keeping the mitochondrial antioxidant defense system operational.

KGDHC is a significant source of ROS

Or, more precisely, the E3 component of KGDHC is a substantial source of ROS in mitochondria. Of note, the E3 component of KGDHC is genetically and physically identical to that of several other E3-bearing enzymes (pyruvate dehydrogenase complex (PDHC), branched-chain α-keto acid dehydrogenase complex (BCKDC), and the glycine cleavage complex; the other protein components are unique to E3-bearing enzyme complexes). E3 is known as dihydrolipoamide dehydrogenase or lipoamide dehydrogenase (commonly used abbreviations are DLD, DLDH, or LADH). For enzymatic activity, E3 requires non-covalently bound FAD (Koike et al., 1974; Patel and Roche, 1990; Reed and Hackert, 1990). E3 is the most abundant flavoprotein in muscle and brain mitochondria (Kunz and Gellerich, 1993). It is not known whether E3 is present as a stand-alone, non-complex-bound enzyme in the mitochondrial matrix. When isolated, E3 exhibits multiple enzymatic activities such as e.g., diaphorase (Massey, 1960) that is capable of reducing quinones at the expense of NADH, or proteinase (reviewed elsewhere (Gibson et al., 2010)). Again, it is not known whether E3 can catalyze these reactions when it is integrated in the proper enzyme complexes.

E3 can generate superoxide and hydrogen peroxide. KGDHC is the major source of H2O2 in the mitochondria in resting state when the ratio of NAD+/NADH is low (Starkov et al., 2004; Tretter and Adam-Vizi, 2004; Tretter and Adam-Vizi, 2005). ROS production has been shown with isolated purified KGDHC (Starkov et al., 2004; Tretter and Adam-Vizi, 2004) and PDHC (Starkov et al., 2004) and in isolated mouse brain mitochondria (Starkov et al., 2004). Mice genetically rendered deficient in E3 by 50% by suppressing Dld gene expression exhibited about 55% of enzymatic activity of KGDHC in brain mitochondria (the activity of PDHC was depleted by only ∼20%, likely because of the differences in the assembly of PDHC and KGDHC complexes). Brain mitochondria isolated from these Dld+/−; mice exhibited about 50% less ROS production with α-ketoglutarate as well as with succinate.On the other hand, mice rendered deficient in KGDHC activity by suppressing the expression of the E2k component (DLST+/− mice) also exhibited about 58% of KGDHC activity in brain mitochondria (Yang et al., 2009), yet the ROS production was normal (these data were not published). This indicates that the source of ROS in KGDHC was E3 with electrons coming from either α-ketoglutarate or NADH (Starkov et al., 2004). It would also explain why the ROS production was suppressed when mitochondria oxidized the succinate in State 4 (Starkov et al., 2004). It is believed that under such conditions ROS are generated at Complex I of the respiratory chain because of reverse electron transfer from the succinate. However, the mitochondrial pyridine nucleotide pool becomes over-reduced under such conditions, which prompts ROS production from other enzymes capable of it which are linked to pyridine nucleotide pool,, such as KGDHC. Thus, ROS production in State 4 in mitochondria oxidizing succinate is a sum of Complex I-generated ROS and ROS generated by other enzymes linked to the NAD pool in the mitochondrial matrix.

Although E3 is a part of several enzyme complexes including KGDHC and PDHC, there is greater impairment of KGDHC than of PDHC activity in E3-deficient mitochondria (Klivenyi et al., 2004; Starkov et al., 2004). The data strongly indicate that KGDHC is a primary site of ROS production in normally functioning mitochondria (Starkov et al., 2004).

This ROS production appears to be pathologically important since inhibitors of KGDHC protect against in vitro hypoxia (Huang et al., 2005) and glutamate toxicity (Zündorf et al., 2009) in parallel with blocking ROS production.

Isolated E3 also produces ROS (Bunik and Sievers, 2002). The ROS production from KGDHC is stimulated by low availability of its natural electron acceptor, NAD+ (Starkov et al., 2004; Tretter and Adam-Vizi, 2004). The dependence on NAD+/NADH provides a direct link to metabolism.

Mutations in the human Dld gene encoding E3 result in the inherited deficiency of the E3 subcomponent of KGDHC with severe or even lethal consequences. The disease-causing mutations involve either the cofactor-binding sites (I12T, K37E, G194C, M326V, I358T), the disulfide redox center (P453L) or the dimerization region (E340K, D444V, R460G) (see Ambrus et al., 2011 for the references). Recently, researchers led by Adam-Vizi (Ambrus et al., 2011) investigated the most important pathogenic mutants of Dld by using site-directed mutagenesis of human Dld; the mutated proteins were expressed in Escherichia coli, isolated, purified and studied with the help of an array of biochemical, structural and biophysical methods. The authors found that G194C, P453L, E340K and D444V mutants exhibited significantly enhanced ROS generation. It is interesting that the location of the mutation in E3 or the conformation changes in the enzyme caused by these mutations had no apparent relation to the enhanced ROS generation. Two ROS-enhancing mutations were at the homodimer interface (E340K, D444V), one at the disulfide-exchange site (P453L) and one at the FAD/pyridine nucleotide binding site (G194C); however, other mutations at the same locations failed to affect ROS generation. There were also no correlation between the changes in the physiological enzymatic activity of E3 and enhanced ROS production. Moreover, G194C mutation did not affect the enzymatic activity of E3 yet significantly stimulated ROS generation. It is interesting that this mutation is frequently associated with E3-deficiency common among Ashkenazi Jews (Shaag et al., 1999). Overall, the data imply that the ROS-generating activity of E3 could potentially be one of the important pathogenic factors in the clinical manifestation of E3-deficiencies associated with the mutations in Dld gene (Ambrus et al., 2011).

The H2O2 production by E3 was studied by Vinogradov's group on heart submitochondrial particles and isolated permeabilized heart mitochondria. Earlier, these researchers found that a fraction of matrix located proteins in bovine heart mitochondria can catalyze NADH-supported, ammonium-stimulated H2O2 production (Grivennikova et al., 2008). The key ROS producing enzyme in this fraction was later identified as dihydrolipoamide dehydrogenase (Kareyeva et al., 2012). Using alamethicin-permeabilized heart mitochondria, authors demonstrated that more than half of H2O2 production can be attributed to dihydrolipoamide dehydrogenase (alamethicin is a pore-forming peptide that is used in vitro to permeabilize mitochondria in order to gain unrestricted access to their matrix side. This allows precise experimental control of the pools of small molecules such as e.g. pyridine nucleotides or glutathione). In the presence of ammonium that stimulates dihydrolipoamide dehydrogenase activity most of the total H2O2 production (∼90%) in alamethicin-permeabilized rat heart mitochondria was catalyzed by dihydrolipoamide dehydrogenase (Kareyeva et al., 2012). Recently, using a soluble form of Dld (pig heart DLDH obtained from Calzyme, U.S.A.) they also demonstrated that H2O2 production attributed to DLDH was dependent on the NAD+/NADH ratio and exhibited first order dependence on O2 concentration in the medium. Authors (Kareyeva et al., 2012) commented that the latter fact creates an apparent physiological paradox when the most ROS production by mitochondria is expected only upon significant reduction of their pyridine nucleotide pool whereas such a situation can arise only in deep hypoxia when ROS production is expected to be minimal due to its first-order nature of oxygen reactivity. This led the authors to predict that a burst of mitochondrial ROS production could be expected upon normoxic reperfusion of anoxic tissue because anaerobically deactivated complex I is only slowly acquiring its NADH oxidizing capacity upon the onset of normoxia (Maklashina et al., 2002).

It should however be noted that oxygen accessibility to the oxygen reactive site in a protein-bound flavin (which is considered to be the site of ROS generation) in soluble DLDH may differ from that in a more physiologically relevant situation with enzyme complex-bound E3, e.g. in KGDHC or PDHC or other E3-bearing enzyme complexes. The binding itself is supposed to affect the conformation of the E3 protein, which is expected to affect the oxygen accessibility, the redox properties of the flavin and its reactivity with oxygen at its reactive site (4a position in the isoalloxazine ring (Kareyeva et al., 2012)). Nevertheless, these results suggest that E3-mediated ROS production could be of importance in oxidative stress and tissue damage upon ischemia and reperfusion. To note, ROS production by KGDHC is stimulated at lower (6.7–7.0) pH relevant to ischemia/reperfusion (Ambrus et al., 2009).

Concluding remarks

Although the fact of ROS generation by the E3 component of KGDHC is – in our opinion – well established, more work has to be done to demonstrate its pathophysiological role in oxidative stress at the level of organisms and to reveal the role of other E3-bearing enzymes in ROS production in different tissues. It would be of great interest to examine whether ROS-generation promoting point mutationsin E3 are present in brain tissue from humans affected by neurodegenerative diseases such as e.g., Alzheimer's or Parkinson's diseases. Hypothetically, such mutations do not necessarily have to be inherited; they can be acquired during the lifetime of an individual for example due to an exposure to pesticides or other environmental toxins. Another important goal is to establish whether the E3 enzyme is present in free, non-bound form in the matrix of mitochondria, and to study the rules and mechanisms governing its assembly into the enzyme complexes. It would also be of interest to evaluate the role of KGDHC (or other E3-bearing enzymes) in the oxidative stress associated with ischemia and reperfusion. Unfortunately, these studies at present are somewhat hindered by the absence of specific inhibitors acting at the E3 NAD+ binding site, which is most likely the site of ROS production.

Acknowledgments

This work was supported by the grant AG 14930 from the National Institutes of Health/National Institute on Aging.

References

  1. Albers DS, Augood SJ, Park LC, Browne SE, Martin DM, Adamson J, Hutton M, Standaert DG, Vonsattel JP, Gibson GE, Beal MF. Frontal lobe dysfunction in progressive supranuclear palsy: evidence for oxidative stress and mitochondrial impairment. J Neurochem. 2000;74(2):878–881. doi: 10.1046/j.1471-4159.2000.740878.x. [DOI] [PubMed] [Google Scholar]
  2. Ambrus A, Tretter L, Adam-Vizi V. Inhibition of the alpha-ketoglutarate dehydrogenase-mediated reactive oxygen species generation by lipoic acid. J Neurochem. 2009;109(Suppl. 1):222–229. doi: 10.1111/j.1471-4159.2009.05942.x. [DOI] [PubMed] [Google Scholar]
  3. Ambrus A, Torocsik B, Tretter L, Ozohanics O, Adam-Vizi V. Stimulation of reactive oxygen species generation by disease-causing mutations of lipoamide dehydrogenase. Hum Mol Genet. 2011;20(15):2984–2995. doi: 10.1093/hmg/ddr202. [DOI] [PubMed] [Google Scholar]
  4. Andreyev AY, Kushnareva YE, Starkov AA. Mitochondrial metabolism of reactive oxygen species. Biochemistry (Mosc) 2005;70(2):200–214. doi: 10.1007/s10541-005-0102-7. [DOI] [PubMed] [Google Scholar]
  5. Bunik VI. 2-Oxo acid dehydrogenase complexes in redox regulation. Eur J Biochem. 2003;270(6):1036–1042. doi: 10.1046/j.1432-1033.2003.03470.x. [DOI] [PubMed] [Google Scholar]
  6. Bunik VI, Sievers C. Inactivation of the 2-oxo acid dehydrogenase complexes upon generation of intrinsic radical species. Eur J Biochem. 2002;269(20):5004–5015. doi: 10.1046/j.1432-1033.2002.03204.x. [DOI] [PubMed] [Google Scholar]
  7. Bunik VI, Buneeva OA, Lvova NB, Gomazkova VS. Structural and functional peculiarities of alpha-ketoglutarate dehydrogenase with non-interacting active sites. Biochem Int. 1989;18(3):561–571. [PubMed] [Google Scholar]
  8. Bunik VI, Buneeva OA, Gomazkova VS. Change in alpha-ketoglutarate dehydrogenase cooperative properties due to dihydrolipoate and NADH. FEBS Lett. 1990;269(1):252–254. doi: 10.1016/0014-5793(90)81166-l. [DOI] [PubMed] [Google Scholar]
  9. Bunik V, Shoubnikova A, Loeffelhardt S, Bisswanger H, Borbe HO, Follmann H. Using lipoate enantiomers and thioredoxin to study the mechanism of the 2-oxoacid-dependent dihydrolipoate production by the 2-oxoacid dehydrogenase complexes. FEBS Lett. 1995;371(2):167–170. doi: 10.1016/0014-5793(95)00904-n. [DOI] [PubMed] [Google Scholar]
  10. Bunik V, Follmann H, Bisswanger H. Activation of mitochondrial 2-oxoacid dehydrogenases by thioredoxin. Biol Chem. 1997;378(10):1125–1130. doi: 10.1515/bchm.1997.378.10.1125. [DOI] [PubMed] [Google Scholar]
  11. Butterworth RF, Besnard AM. Thiamine-dependent enzyme changes in temporal cortex of patients with Alzheimer's disease. Metab Brain Dis. 1990;5(4):179–184. doi: 10.1007/BF00997071. [DOI] [PubMed] [Google Scholar]
  12. Butterworth RF, Kril JJ, Harper CG. Thiamine-dependent enzyme changes in the brains of alcoholics: relationship to the Wernicke–Korsakoff syndrome. Alcohol Clin Exp Res. 1993;17(5):1084–1088. doi: 10.1111/j.1530-0277.1993.tb05668.x. [DOI] [PubMed] [Google Scholar]
  13. Cabiscol E, Piulats E, Echave P, Herrero E, Ros J. Oxidative stress promotes specific protein damage in Saccharomyces cerevisiae. J Biol Chem. 2000;275(35):27393–27398. doi: 10.1074/jbc.M003140200. [DOI] [PubMed] [Google Scholar]
  14. Chinopoulos C, Tretter L, Adam-Vizi V. Depolarization of in situ mitochondria due to hydrogen peroxide-induced oxidative stress in nerve terminals: inhibition of alpha-ketoglutarate dehydrogenase. J Neurochem. 1999;73(1):220–228. doi: 10.1046/j.1471-4159.1999.0730220.x. [DOI] [PubMed] [Google Scholar]
  15. Chinopoulos C, Gerencser AA, Mandi M, Mathe K, Torocsik B, Doczi J, Turiak L, Kiss G, Konrad C, Vajda S, Vereczki V, Oh RJ, Adam-Vizi V. Forward operation of adenine nucleotide translocase during F0F1-ATPase reversal: critical role of matrix substrate-level phosphorylation. FASEB J. 2010;24(7):2405–2416. doi: 10.1096/fj.09-149898. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Correa JG, Stoppani AO. Catecholamines enhance dihydrolipoamide dehydrogenase inactivation by the copper Fenton system. Enzyme protection by copper chelators. Free Radic Res. 1996;24(4):311–322. doi: 10.3109/10715769609088028. [DOI] [PubMed] [Google Scholar]
  17. Gibson GE, Sheu KF, Blass JP, Baker A, Carlson KC, Harding B, Perrino P. Reduced activities of thiamine-dependent enzymes in the brains and peripheral tissues of patients with Alzheimer's disease. Arch Neurol. 1988;45(8):836–840. doi: 10.1001/archneur.1988.00520320022009. [DOI] [PubMed] [Google Scholar]
  18. Gibson GE, Starkov A, Blass JP, Ratan RR, Beal MF. Cause and consequence: mitochondrial dysfunction initiates and propagates neuronal dysfunction, neuronal death and behavioral abnormalities in age-associated neurodegenerative diseases. Biochim Biophys Acta. 2010;1802(1):122–134. doi: 10.1016/j.bbadis.2009.08.010. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Gibson GE, Zhang H, Sheu KF, Bogdanovich N, Lindsay JG, Lannfelt L, Vestling M, Cowburn RF. Alpha-ketoglutarate dehydrogenase in Alzheimer brains bearing the APP670/671 mutation. Ann Neurol. 1998;44(4):676–681. doi: 10.1002/ana.410440414. [DOI] [PubMed] [Google Scholar]
  20. Gibson GE, Zhang H, Sheu KR, Park LC. Differential alterations in antioxidant capacity in cells from Alzheimer patients. Biochim Biophys Acta. 2000;1502(3):319–329. doi: 10.1016/s0925-4439(00)00057-0. [DOI] [PubMed] [Google Scholar]
  21. Gibson GE, Kingsbury AE, Xu H, Lindsay JG, Daniel S, Foster OJ, Lees AJ, Blass JP. Deficits in a tricarboxylic acid cycle enzyme in brains from patients with Parkinson's disease. Neurochem Int. 2003;43(2):129–135. doi: 10.1016/s0197-0186(02)00225-5. [DOI] [PubMed] [Google Scholar]
  22. Gibson GE, Starkov A, Blass JP, Ratan RR, Beal MF. Cause and consequence: mitochondrial dysfunction initiates and propagates neuronal dysfunction, neuronal death and behavioral abnormalities in age-associated neurodegenerative diseases. Biochim Biophys Acta. 2010;1802(1):122–134. doi: 10.1016/j.bbadis.2009.08.010. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Gourlay LJ, Bhella D, Kelly SM, Price NC, Lindsay JG. Structure-function analysis of recombinant substrate protein 22 kDa (SP-22). A mitochondrial 2-CYS peroxiredoxin organized as a decameric toroid. J Biol Chem. 2003;278(35):32631–32637. doi: 10.1074/jbc.M303862200. [DOI] [PubMed] [Google Scholar]
  24. Grivennikova VG, Cecchini G, Vinogradov AD. Ammonium-dependent hydrogen peroxide production by mitochondria. FEBS Lett. 2008;582(18):2719–2724. doi: 10.1016/j.febslet.2008.06.054. [DOI] [PubMed] [Google Scholar]
  25. Hamada M, Koike K, Nakaula Y, Hiraoka T, Koike M. A kinetic study of the alpha-keto acid dehydrogenase complexes from pig heart mitochondria. J Biochem. 1975;77(5):1047–1056. doi: 10.1093/oxfordjournals.jbchem.a130805. [DOI] [PubMed] [Google Scholar]
  26. Haxby JV, Grady CL, Duara R, Schlageter N, Berg G, Rapoport SI. Neocortical metabolic abnormalities precede nonmemory cognitive defects in early Alzheimer's type dementia. Arch Neurol. 1986;43(9):882–885. doi: 10.1001/archneur.1986.00520090022010. [DOI] [PubMed] [Google Scholar]
  27. Hinerfeld D, Traini MD, Weinberger RP, Cochran B, Doctrow SR, Harry J, Melov S. Endogenous mitochondrial oxidative stress: neurodegeneration, proteomic analysis, specific respiratory chain defects, and efficacious antioxidant therapy in superoxide dismutase 2 null mice. J Neurochem. 2004;88(3):657–667. doi: 10.1046/j.1471-4159.2003.02195.x. [DOI] [PubMed] [Google Scholar]
  28. Huang HM, Ou HC, Chen HL, Hou RC, Jeng KC. Protective effect of alpha-keto-beta-methyl-n-valeric acid on BV-2 microglia under hypoxia or oxidative stress. Ann N Y Acad Sci. 2005;1042:272–278. doi: 10.1196/annals.1338.049. [DOI] [PubMed] [Google Scholar]
  29. Humphries KM, Szweda LI. Selective inactivation of alpha-ketoglutarate dehy drogenase and pyruvate dehydrogenase: reaction of lipoic acid with 4-hydroxy-2-nonenal. Biochemistry. 1998;37(45):15835–15841. doi: 10.1021/bi981512h. [DOI] [PubMed] [Google Scholar]
  30. Humphries KM, Yoo Y, Szweda LI. Inhibition of NADH-linked mitochondrial respiration by 4-hydroxy-2-nonenal. Biochemistry. 1998;37(2):552–557. doi: 10.1021/bi971958i. [DOI] [PubMed] [Google Scholar]
  31. Kareyeva AV, Grivennikova VG, Vinogradov AD. Mitochondrial hydrogen peroxide production as determined by the pyridine nucleotide pool and its redox state. Biochim Biophys Acta. 2012 doi: 10.1016/j.bbabio.2012.03.033. PMID: 22503830 (Epub ahead of print) [DOI] [PubMed] [Google Scholar]
  32. Kiselevsky YV, Ostrovtsova SA, Strumilo SA. Kinetic characterization of the pyruvate and oxoglutarate dehydrogenase complexes from human heart. Acta Biochim Pol. 1990;37(1):135–139. [PubMed] [Google Scholar]
  33. Klivenyi P, Starkov AA, Calingasan NY, Gardian G, Browne SE, Yang L, Bubber P, Gibson GE, Patel MS, Beal MF. Mice deficient in dihydrolipoamide dehydrogenase show increased vulnerability to MPTP, malonate and 3-nitropropionic acid neurotoxicity. J Neurochem. 2004;88(6):1352–1360. doi: 10.1046/j.1471-4159.2003.02263.x. [DOI] [PubMed] [Google Scholar]
  34. Koike K, Hamada M, Tanaka N, Otsuka KI, Ogasahara K, Koike M. Properties and subunit composition of the pig heart 2-oxoglutarate dehydrogenase. J Biol Chem. 1974;249(12):3836–3842. [PubMed] [Google Scholar]
  35. Kumar MJ, Nicholls DG, Andersen JK. Oxidative alpha-ketoglutarate dehydrogenase inhibition via subtle elevations in monoamine oxidase B levels results in loss of spare respiratory capacity: implications for Parkinson's disease. J Biol Chem. 2003;278(47):46432–46439. doi: 10.1074/jbc.M306378200. [DOI] [PubMed] [Google Scholar]
  36. Kunz WS, Gellerich FN. Quantification of the content of fluorescent flavoproteins in mitochondria from liver, kidney cortex, skeletal muscle, and brain. Biochem Med Metab Biol. 1993;50(1):103–110. doi: 10.1006/bmmb.1993.1051. [DOI] [PubMed] [Google Scholar]
  37. LaNoue KF, Schoolwerth AC, Pease AJ. Ammonia formation in isolated rat liver mitochondria. J Biol Chem. 1983;258(3):1726–1734. [PubMed] [Google Scholar]
  38. Lawlis VB, Roche TE. Inhibition of bovine kidney alpha-ketoglutarate dehydrogenase complex by reduced nicotinamide adenine dinucleotide in the presence or absence of calcium ion and effect of adenosine 5′-diphosphate on reduced nicotinamide adenine dinucleotide inhibition. Biochemistry. 1981;20(9):2519–2524. doi: 10.1021/bi00512a024. [DOI] [PubMed] [Google Scholar]
  39. Lyubarev AE, Kurganov BI. Supramolecular organization of tricarboxylic acid cycle enzymes. Biosystems. 1989;22(2):91–102. doi: 10.1016/0303-2647(89)90038-5. [DOI] [PubMed] [Google Scholar]
  40. Maas E, Bisswanger H. Localization of the alpha-oxoacid dehydrogenase multienzyme complexes within the mitochondrion. FEBS Lett. 1990;277(1–2):189–190. doi: 10.1016/0014-5793(90)80840-f. [DOI] [PubMed] [Google Scholar]
  41. Maklashina E, Sher Y, Zhou HZ, Gray MO, Karliner JS, Cecchini G. Effect of anoxia/reperfusion on the reversible active/de-active transition of NADH ubiquinone oxidoreductase (complex I) in rat heart. Biochim Biophys Acta. 2002;1556(1):6–12. doi: 10.1016/s0005-2728(02)00280-3. [DOI] [PubMed] [Google Scholar]
  42. Massey V. The identity of diaphorase and lipoyl dehydrogenase. Biochim Biophys Acta. 1960;37:314–322. doi: 10.1016/0006-3002(60)90239-0. [DOI] [PubMed] [Google Scholar]
  43. Mastrogiacoma F, Lindsay JG, Bettendorff L, Rice J, Kish SJ. Brain protein and alpha-ketoglutarate dehydrogenase complex activity in Alzheimer's disease. Ann Neurol. 1996;39(5):592–598. doi: 10.1002/ana.410390508. [DOI] [PubMed] [Google Scholar]
  44. Mastrogiacomo F, Bergeron C, Kish SJ. Brain alpha-ketoglutarate dehydrogenase complex activity in Alzheimer's disease. J Neurochem. 1993;61(6):2007–2014. doi: 10.1111/j.1471-4159.1993.tb07436.x. [DOI] [PubMed] [Google Scholar]
  45. McCormack JG, Denton RM. The effects of calcium ions and adenine nucleotides on the activity of pig heart 2-oxoglutarate dehydrogenase complex. Biochem J. 1979;180(3):533–544. doi: 10.1042/bj1800533. [DOI] [PMC free article] [PubMed] [Google Scholar]
  46. McMinn CL, Ottaway JH. Studies on the mechanism and kinetics of the 2-oxoglutarate dehydrogenase system from pig heart. Biochem J. 1977;161(3):569–581. doi: 10.1042/bj1610569. [DOI] [PMC free article] [PubMed] [Google Scholar]
  47. Nulton-Persson AC, Starke DW, Mieyal JJ, Szweda LI. Reversible inactivation of alpha-ketoglutarate dehydrogenase in response to alterations in the mitochondrial glutathione status. Biochemistry. 2003;42(14):4235–4242. doi: 10.1021/bi027370f. [DOI] [PubMed] [Google Scholar]
  48. Park LC, Zhang H, Sheu KF, Calingasan NY, Kristal BS, Lindsay JG, Gibson GE. Metabolic impairment induces oxidative stress, compromises inflammatory responses, and inactivates a key mitochondrial enzyme in microglia. J Neurochem. 1999;72(5):1948–1958. doi: 10.1046/j.1471-4159.1999.0721948.x. [DOI] [PubMed] [Google Scholar]
  49. Park LC, Albers DS, Xu H, Lindsay JG, Beal MF, Gibson GE. Mitochondrial impairment in the cerebellum of the patients with progressive supranuclear palsy. J Neurosci Res. 2001;66(5):1028–1034. doi: 10.1002/jnr.10062. [DOI] [PubMed] [Google Scholar]
  50. Patel MS, Roche TE. Molecular biology and biochemistry of pyruvate dehydrogenase complexes. FASEB J. 1990;4(14):3224–3233. doi: 10.1096/fasebj.4.14.2227213. [DOI] [PubMed] [Google Scholar]
  51. Pocernich CB, Butterfield DA. Acrolein inhibits NADH-linked mitochondrial enzyme activity: implications for Alzheimer's disease. Neurotox Res. 2003;5(7):515–520. doi: 10.1007/BF03033161. [DOI] [PubMed] [Google Scholar]
  52. Reed LJ, Hackert ML. Structure–function relationships in dihydrolipoamide acyltransferases. J Biol Chem. 1990;265(16):8971–8974. [PubMed] [Google Scholar]
  53. Rokutan K, Kawai K, Asada K. Inactivation of 2-oxoglutarate dehydrogenase in rat liver mitochondria by its substrate and t-butyl hydroperoxide. J Biochem. 1987;101(2):415–422. doi: 10.1093/oxfordjournals.jbchem.a121926. [DOI] [PubMed] [Google Scholar]
  54. Shaag A, Saada A, Berger I, Mandel H, Joseph A, Feigenbaum A, Elpeleg ON. Molecular basis of lipoamide dehydrogenase deficiency in Ashkenazi Jews. Am J Med Genet. 1999;82(2):177–182. [PubMed] [Google Scholar]
  55. Sheu KF, Blass JP. The alpha-ketoglutarate dehydrogenase complex. Ann N Y Acad Sci. 1999;893:61–78. doi: 10.1111/j.1749-6632.1999.tb07818.x. [DOI] [PubMed] [Google Scholar]
  56. Starkov AA, Fiskum G, Chinopoulos C, Lorenzo BJ, Browne SE, Patel MS, Beal MF. Mitochondrial alpha-ketoglutarate dehydrogenase complex generates reactive oxygen species. J Neurosci. 2004;24(36):7779–7788. doi: 10.1523/JNEUROSCI.1899-04.2004. [DOI] [PMC free article] [PubMed] [Google Scholar]
  57. Sumegi B, Srere PA. Complex I binds several mitochondrial NAD-coupled dehydrogenases. J Biol Chem. 1984;259(24):15040–15045. [PubMed] [Google Scholar]
  58. Terwel D, Bothmer J, Wolf E, Meng F, Jolles J. Affected enzyme activities in Alzheimer's disease are sensitive to antemortem hypoxia. J Neurol Sci. 1998;161(1):47–56. doi: 10.1016/s0022-510x(98)00240-8. [DOI] [PubMed] [Google Scholar]
  59. Tretter L, Adam-Vizi V. Inhibition of Krebs cycle enzymes by hydrogen peroxide: a key role of [alpha]-ketoglutarate dehydrogenase in limiting NADH production under oxidative stress. J Neurosci. 2000;20(24):8972–8979. doi: 10.1523/JNEUROSCI.20-24-08972.2000. [DOI] [PMC free article] [PubMed] [Google Scholar]
  60. Tretter L, Adam-Vizi V. Generation of reactive oxygen species in the reaction catalyzed by alpha-ketoglutarate dehydrogenase. J Neurosci. 2004;24(36):7771–7778. doi: 10.1523/JNEUROSCI.1842-04.2004. [DOI] [PMC free article] [PubMed] [Google Scholar]
  61. Tretter L, Adam-Vizi V. Alpha-ketoglutarate dehydrogenase: a target and generator of oxidative stress. Philos Trans R Soc Lond B Biol Sci. 2005;360(1464):2335–2345. doi: 10.1098/rstb.2005.1764. [DOI] [PMC free article] [PubMed] [Google Scholar]
  62. Wagenknecht T, Francis N, DeRosier DJ. Alpha-ketoglutarate dehydrogenase complex may be heterogeneous in quaternary structure. J Mol Biol. 1983;165(3):523–539. doi: 10.1016/s0022-2836(83)80217-4. [DOI] [PubMed] [Google Scholar]
  63. Wan B, LaNoue KF, Cheung JY, Scaduto RC., Jr Regulation of citric acid cycle by calcium. J Biol Chem. 1989;264(23):13430–13439. [PubMed] [Google Scholar]
  64. Xu H, Jeitner T, Zhang H, Gibson GE. α-Ketoglutarate dehydrogenase and oxidative stress. J Neurochem. 2001;78S:132. [Google Scholar]
  65. Yang L, Shi Q, Ho DJ, Starkov AA, Wille EJ, Xu H, Chen HL, Zhang S, Stack CM, Calingasan NY, Gibson GE, Beal MF. Mice deficient in dihydrolipoyl succinyl transferase show increased vulnerability to mitochondrial toxins. Neurobiol Dis. 2009;36(2):320–330. doi: 10.1016/j.nbd.2009.07.023. [DOI] [PMC free article] [PubMed] [Google Scholar]
  66. Zündorf G, Kahlert S, Bunik VI, Reiser G. [Alpha]-ketoglutarate dehydrogenase contributes to production of reactive oxygen species in glutamate-stimulated hippocampal neurons in situ. Neuroscience. 2009;158(2):610–616. doi: 10.1016/j.neuroscience.2008.10.015. [DOI] [PubMed] [Google Scholar]

RESOURCES