hydrogenosome

GO:0042566 · Membrane organelle · Membrane bounded organelle · Proposed

A spherical, membrane-bounded organelle found in some anaerobic protozoa, which participates in ATP and molecular hydrogen formation. [GO:0042566]

Part of: GO:0005737 — cytoplasm (no local record)

Has part: hydrogenosome lumen (GO:0034492); hydrogenosomal membrane (GO:0046859)

UniProt location names: UniProt Consortium, CC BY 4.0. Reference label and route sources.

Components

Component	Type	Part of / acts on	Grounding	Essential	Role
hydrogenosomal membrane	Lipid	part of	`GO:0046859`	ESSENTIAL	Double bounding membrane that encloses the hydrogenosome matrix and separates ATP- and hydrogen-producing enzymes from the cytosol. `PMID:4750424` Lindmark and Muller 1973 described a particulate hydrogen-producing organelle in Tritrichomonas foetus. `DOI:10.1111/jeu.12922` Tachezy 2022 reviews hydrogenosomes as mitochondrion-related organelles of anaerobic eukaryotes.
hydrogenosomal pyruvate metabolism and hydrogen-production enzymes	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	UNKNOWN	Matrix enzymes that convert pyruvate into acetate, ATP and molecular hydrogen under anaerobic conditions. `PMID:4750424` Lindmark and Muller 1973 linked the organelle to hydrogen production in trichomonads. `DOI:10.1016/j.ijpara.2011.10.001` Schneider et al. 2011 identified hydrogenosomal proteins involved in pyruvate metabolism, substrate-level phosphorylation and hydrogen production.
hydrogenosomal iron-sulfur cluster assembly machinery	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	UNKNOWN	Mitochondrial-type ISC factors that assemble iron-sulfur centers in the hydrogenosome. `DOI:10.1073/pnas.0401319101` Sutak et al. 2004 localized mitochondrial-type iron-sulfur center assembly to Trichomonas vaginalis hydrogenosomes.
hydrogenosomal protein-import machinery	Protein	acts on	Reviewed label only (reviewed name; no accession asserted)	UNKNOWN	Mitochondrion-related machinery that recognizes N-terminal presequences and imports nuclear-encoded proteins into the hydrogenosome. `DOI:10.1073/pnas.0500349102` Dolezal et al. 2005 found that Giardia mitosomes and trichomonad hydrogenosomes share a protein targeting mode. `DOI:10.1073/pnas.93.18.9651` Bui et al. 1996 found N-terminal processing of hydrogenosomal Hsp60, consistent with import of nuclear-encoded matrix proteins.

Taxonomic distribution

NCBITaxon:2759 Eukaryota — RARE: Hydrogenosomes occur patchily in anaerobic microbial eukaryotes and represent independently modified mitochondria rather than a conserved eukaryotic state. [DOI:10.1111/jeu.12922]
NCBITaxon:5722 Trichomonas vaginalis — COMMON: The parasite contains abundant hydrogenosomes that have been biochemically and proteomically characterized. [DOI:10.1016/j.ijpara.2011.10.001]

Canonical examples

NCBITaxon:5722 Trichomonas vaginalis — Parabasalid parasite in which hydrogenosomal metabolism, iron-sulfur cluster assembly, protein targeting and the organelle proteome have been experimentally studied. [DOI:10.1016/j.ijpara.2011.10.001]

Functions

anaerobic ATP and molecular hydrogen production — Hydrogenosomal pyruvate metabolism supports anaerobic ATP production by substrate-level phosphorylation while releasing molecular hydrogen.
- PMID:4750424 Lindmark and Muller 1973 isolated the hydrogen-producing organelle that gave hydrogenosomes their name.
- DOI:10.1016/j.ijpara.2011.10.001 Schneider et al. 2011 cataloged hydrogenosomal enzymes for pyruvate metabolism and substrate-level phosphorylation.
hydrogenosomal iron-sulfur cluster assembly — Hydrogenosomes retain mitochondrial-type ISC machinery that assembles iron-sulfur centers.
- DOI:10.1073/pnas.0401319101 Sutak et al. 2004 showed that iron-sulfur center assembly occurs in Trichomonas vaginalis hydrogenosomes.
hydrogenosomal matrix protein import — Nuclear-encoded hydrogenosomal matrix proteins are targeted to the organelle through N-terminal presequences.
- DOI:10.1073/pnas.0500349102 Dolezal et al. 2005 compared targeting signals in trichomonad hydrogenosomes and Giardia mitosomes.

Mechanism graphs

Hydrogenosomal enzymes convert pyruvate into ATP and molecular hydrogen (FUNCTION)

Hydrogenosomal import and ISC assembly load the organelle matrix with enzymes that oxidize pyruvate and support substrate-level phosphorylation with proton reduction to molecular hydrogen.

Subject	Predicate	Object	Evidence
hydrogenosomal membrane	bounds	hydrogenosome	`DOI:10.1111/jeu.12922` Tachezy 2022 reviews hydrogenosomes as membrane-bounded mitochondrion-related organelles.
hydrogenosomal protein-import machinery	imports	hydrogenosomal pyruvate metabolism and hydrogen-production enzymes	`DOI:10.1073/pnas.0500349102` Dolezal et al. 2005 studied presequence targeting into trichomonad hydrogenosomes.
hydrogenosomal pyruvate metabolism and hydrogen-production enzymes	accumulate in	hydrogenosome lumen	`DOI:10.1016/j.ijpara.2011.10.001` Schneider et al. 2011 identified the Trichomonas hydrogenosome proteome.
hydrogenosomal iron-sulfur cluster assembly machinery	supports	hydrogenosomal iron-sulfur cluster assembly	`DOI:10.1073/pnas.0401319101` Sutak et al. 2004 localized mitochondrial-type iron-sulfur assembly proteins to hydrogenosomes.
hydrogenosomal pyruvate metabolism and hydrogen-production enzymes	convert	pyruvate	`PMID:4750424` Lindmark and Muller 1973 linked the organelle to pyruvate metabolism and hydrogen production.
hydrogenosomal pyruvate metabolism and hydrogen-production enzymes	produce	ATP	`DOI:10.1016/j.ijpara.2011.10.001` Schneider et al. 2011 cataloged the Trichomonas hydrogenosomal energy metabolism proteins.
hydrogenosomal pyruvate metabolism and hydrogen-production enzymes	produce	molecular hydrogen	`DOI:10.1016/j.ijpara.2011.10.001` Schneider et al. 2011 cataloged the Trichomonas hydrogenosomal energy metabolism proteins.

Discussions

CURATION_TODO (OPEN): Resolve exact source-neutral groundings for hydrogenosomal protein-import factors and energy-metabolism enzyme families. The first record groups divergent nuclear-encoded hydrogenosomal import and energy proteins. Exact family-level CURIEs for every grouped factor were not curated.

Evidence

PMID:4750424 Lindmark and Muller 1973, Hydrogenosome, a cytoplasmic organelle of the anaerobic flagellate Tritrichomonas foetus, and its role in pyruvate metabolism, Journal of Biological Chemistry.
DOI:10.1073/pnas.93.18.9651 Bui et al. 1996, A common evolutionary origin for mitochondria and hydrogenosomes, Proceedings of the National Academy of Sciences.
DOI:10.1073/pnas.0401319101 Sutak et al. 2004, Mitochondrial-type assembly of iron-sulfur centers in the hydrogenosomes of the amitochondriate eukaryote Trichomonas vaginalis, Proceedings of the National Academy of Sciences.
DOI:10.1073/pnas.0500349102 Dolezal et al. 2005, Giardia mitosomes and trichomonad hydrogenosomes share a common mode of protein targeting, Proceedings of the National Academy of Sciences.
DOI:10.1016/j.ijpara.2011.10.001 Schneider et al. 2011, The Trichomonas vaginalis hydrogenosome proteome is highly reduced relative to mitochondria, yet complex compared with mitosomes, International Journal for Parasitology.
DOI:10.1111/jeu.12922 Tachezy 2022, Hydrogenosomes and mitosomes: Mitochondria of anaerobic eukaryotes, Journal of Eukaryotic Microbiology.

Curation history

2026-09-10T03:24:10Z claude · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-10T03:25:09Z claude · EXPANDED_RECORD — Added hydrogenosome membrane and lumen parthood, membrane, pyruvate-metabolism, Fe-S assembly and protein-import components, rare eukaryotic and Trichomonas taxonomic scope, Trichomonas vaginalis as a canonical example, ATP/hydrogen production, Fe-S assembly and protein-import functions, a pyruvate-to-ATP/hydrogen graph, and grounding TODOs for import and energy components.
2026-09-10T03:33:25Z claude · ADDRESSED_PR_REVIEW — Addressed PR #310 review issues #311, #312 and #313 by removing uncurated component gene-symbol groups, retargeting the ISC graph edge to iron-sulfur cluster assembly, and splitting ATP from molecular hydrogen in the causal graph.
2026-09-20T21:58:46Z codex · ADDRESSED_REVIEW — Retyped the hydrogenosome lumen graph node as CELLULAR_LOCALIZATION.

Source: data/structures/membrane_organelle/hydrogenosome.yaml