Acetate formation in the energy metabolism of parasitic helminths and protists.
Level 5 - mechanism / opinion, no new human data
Narrative review of parasite biochemistry and metabolic pathways with no human clinical data.
PubMed 20085767 · doi:10.1016/j.ijpara.2009.12.006
What was done
This narrative review synthesized biochemical and comparative genomic evidence regarding the pathways of acetate formation and excretion in parasitic helminths (such as Fasciola hepatica, Haemonchus contortus, and Ascaris suum) and parasitic protists (Giardia lamblia, Entamoeba histolytica, Trichomonas vaginalis, Trypanosoma, and Leishmania spp.).
What was found
The abstract reports qualitative metabolic pathways rather than quantitative experimental numbers. Acetate serves as a primary end product of energy metabolism in various parasites via two main substrate-level phosphorylation mechanisms: cytosolic acetyl-CoA synthetase (ACS), which directly couples to ATP synthesis, or organellar acetate:succinate CoA-transferase (ASCT), which yields succinyl-CoA for ATP generation via succinyl-CoA synthetase. The authors identify three distinct subfamilies of CoA-transferase family I (subfamily IA in trypanosomatid mitochondria, IB in parasitic worm mitochondria, and IC in hydrogenosomes) that share a catalytic mechanism despite low sequence homology. These acetate-generating pathways do not occur in mammalian hosts.
Why it matters
Because acetate excretion is central to energy metabolism in diverse human and animal parasites but absent in their mammalian hosts, the enzymes responsible (particularly the ASCT subfamilies and ACS) represent potential selective targets for antiparasitic therapeutics.
Limits
The abstract provides no primary quantitative data, sample sizes, or systematic review methodology. Drug discovery implications remain theoretical biochemical hypotheses, as the abstract does not assess actual enzyme inhibitors, target essentiality screens, or in vivo anti-parasitic efficacy.
Cited by
- supports Parasites utilize glutamine fermentation and mitochondrial substrate-level phosphorylation to survive in host tissues.