The human Krebs cycle 2-oxoglutarate dehydrogenase complex creates an additional source of superoxide/hydrogen peroxide from 2-oxoadipate as alternative substrate

Natalia S. Nemeria, Gary Gerfen, Elena Guevara, Pradeep Reddy Nareddy, Michal Szostak, Frank Jordan

Research output: Contribution to journalArticle

11 Scopus citations


Recently, we reported that the human 2-oxoglutarate dehydrogenase (hE1o) component of the 2-oxoglutarate dehydrogenase complex (OGDHc) could produce the reactive oxygen species superoxide and hydrogen peroxide (detected by chemical means) from its substrate 2-oxoglutarate (OG), most likely concurrently with one-electron oxidation by dioxygen of the thiamin diphosphate (ThDP)-derived enamine intermediate to a C2α-centered radical (detected by Electron Paramagnetic Resonance) [Nemeria et al., 2014 [17]; Ambrus et al. 2015 [18]]. We here report that hE1o can also utilize the next higher homologue of OG, 2-oxoadipate (OA) as a substrate according to multiple criteria in our toolbox: (i) Both E1o-specific and overall complex activities (NADH production) were detected using OA as a substrate; (ii) Two post-decarboxylation intermediates were formed by hE1o from OA, the ThDP-enamine and the C2α-hydroxyalkyl-ThDP, with nearly identical rates for OG and OA; (iii) Both OG and OA could reductively acylate lipoyl domain created from dihydrolipoyl succinyltransferase (E2o); (iv) Both OG and OA gave α-ketol carboligaton products with glyoxylate, but with opposite chirality; a finding that could be of utility in chiral synthesis; (v) Dioxygen could oxidize the ThDP-derived enamine from both OG and OA, leading to ThDP-enamine radical and generation of superoxide and H2O2. While the observed oxidation-reduction with dioxygen is only a side reaction of the predominant physiological product glutaryl-CoA, the efficiency of superoxide/ H2O2 production was 7-times larger from OA than from OG, making the reaction of OGDHc with OA one of the important superoxide/ H2O2 producers among 2-oxo acid dehydrogenase complexes in mitochondria.

Original languageEnglish (US)
Pages (from-to)644-654
Number of pages11
JournalFree Radical Biology and Medicine
StatePublished - Jul 1 2017



  • 2-oxoadipate
  • 2-oxoglutarate dehydrogenase
  • 2-oxoglutarate dehydrogenase complex
  • EPR
  • Superoxide and HO generation
  • ThDP-enamine radical
  • α-ketol carboligaton products

ASJC Scopus subject areas

  • Biochemistry
  • Physiology (medical)

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