Ethylmalonic encephalopathy (WP5030)

Cysteine is converted into pyruvate and hydrogen sulfide (H2S) through desulphuration and deamination. Then, H2S is oxidised by SQR, after which ETHE1 takes care of converting into sulfite (SO3 2-). One disorder named Ethylmalonic encephalopathy (EE) is linked to this pathway, a rare mitochondrial disease caused by variants within the ETHE1 gene. This pathway was inspired by Chapter 9 (edition 4) of the book of Blau (ISBN 3642403360 (978-3642403361)).
last edited


DeSl, Andra, Egonw, Eweitz, Finterly, and Fehrhart

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Homo sapiens


Inborn Errors of Metabolism (IEM) Pathways Rare Diseases


Pathway Ontology: ethylmalonic encephalopathy pathway

Disease Ontology: ethylmalonic encephalopathy


Label Type Compact Identifier
OXPHOS pathway Pathway wikipathways:WP78
Cysteine Metabolite chebi:15356
Electron Metabolite chebi:10545
Rhodanese Protein uniprot:Q16762
H2S Metabolite chebi:16136
ETHE1 Protein uniprot:O95571
CoEnzyme Q Metabolite chebi:46245
SQR Protein eccode:
SO3 2-(sulfite) Metabolite chebi:17359
SOX Protein uniprot:P51687
R-SSH, example:S-sulfanylglutathione Metabolite chebi:58905
Pyruvate Metabolite chebi:32816
O2 Metabolite chebi:15379
R, example:glutathione Metabolite chebi:57925
SO4 2-(sulfate) Metabolite chebi:16189
S2O3 2-(thiosulfate) Metabolite chebi:16094
2 H2O Metabolite chebi:15377


  1. Barth M, Ottolenghi C, Hubert L, Chrétien D, Serre V, Gobin S, et al. Multiple sources of metabolic disturbance in ETHE1-related ethylmalonic encephalopathy. J Inherit Metab Dis. 2010 Dec;33 Suppl 3:S443-53. PubMed Europe PMC Scholia
  2. Ziosi M, Di Meo I, Kleiner G, Gao X-H, Barca E, Sanchez-Quintero MJ, et al. Coenzyme Q deficiency causes impairment of the sulfide oxidation pathway. EMBO Mol Med. 2017 Jan;9(1):96–111. PubMed Europe PMC Scholia
  3. PubMed Europe PMC Scholia