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2‐Oxoglutarate: Oxidation and Role as a Potential Precursor of Cytosolic Acetyl‐CoA for the Synthesis of Acetylcholine in Rat Brain Synaptosomes
Author(s) -
Willoughby Jane,
Craig Fiona E.,
Harvey Stephen A. K.,
Clark John B.
Publication year - 1989
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1989.tb02539.x
Subject(s) - atp citrate lyase , cytosol , aconitase , biochemistry , isocitrate dehydrogenase , enzyme , acetylcholine , citrate synthase , lyase , synaptosome , acetyl coa , dehydrogenase , chemistry , citric acid cycle , oxoglutarate dehydrogenase complex , metabolism , biology , branched chain alpha keto acid dehydrogenase complex , endocrinology , in vitro
The possibility that 2‐oxoglutarate may supply acetyl units for the cytosolic synthesis of acetylcholine in rat brain synaptosomes was investigated. The contribution of [ 14 C]2‐oxoglutarate to the synaptosomal synthesis of [ 14 C]acetylcholine was found to be negligible despite evidence for its uptake and oxidation. The activity of the enzymes NADP‐isocitrate dehydrogenase (EC 1.1.1.42), aconitate hydratase (EC 4.2.1.3), and ATP citrate‐lyase (EC 4.1.3.8) were measured in the synaptosol. NADP‐isocitrate dehydrogenase and aconitate hydratase are present at three‐ to 1.5‐fold higher activities than ATP citrate‐lyase. It seems likely that these enzymes contribute to the metabolism of citrate and prevent detectable formation of cytosolic acetyl‐CoA from exogenously added 2‐oxoglutarate (or citrate). The data further suggest that ATP citrate‐lyase may in part be associated with the mitochondrial fraction.