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Regional and Subcellular Distribution of ATP‐Citrate Lyase and Other Enzymes of Acetyl‐CoA Metabolism in Rat Brain
Author(s) -
Szutowicz A.,
Lysiak W. Z.
Publication year - 1980
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.1471-4159.1980.tb07073.x
Subject(s) - atp citrate lyase , citrate synthase , biochemistry , acetyl coa , pyruvate dehydrogenase complex , choline acetyltransferase , enzyme , biology , lyase , coenzyme a , citric acid cycle , acetyltransferase , lactate dehydrogenase , pyruvate dehydrogenase phosphatase , chemistry , endocrinology , cholinergic , acetylation , reductase , gene
The activities of ATP‐citrate lyase in frog, guinea pig, mouse, rat, and human brain vary from 18 to 30 μ mol/h/g of tissue, being several times higher than choline acetyltransferase activity. Activities of pyruvate dehydrogenase and acetyl coenzyme A synthetase in rat brain are 206 and 18.4 μ mol/h/g of tissue, respectively. Over 70% of the activities of both choline acetyltransferase and ATP‐citrate lyase in secondary fractions are found in synaptosomes. Their preferential localization in synaptosomes and synaptoplasm is supported by RSA values above 2. Acetyl CoA synthetase activity is located mainly in whole brain mitochondria (RSA, 2.33) and its activity in synaptoplasm is low (RSA, 0.25). The activities of pyruvate dehydrogenase, citrate synthase, and carnitine acetyltransferase are present mainly in fractions C and B p . No pyruvate dehydrogenase activity is found in synaptoplasm. Striatum, cerebral cortex, and cerebellum contain similar activities of pyruvate dehydrogenase, citrate synthase, carnitine acetyltransferase, fatty acid synthetase, and acetyl‐CoA hydrolase. Activities of acetyl CoA synthetase, choline acetyltransferase and ATP‐citrate lyase in cerebellum are about 10 and 4 times lower, respectively, than in other parts of the brain. These data indicate preferential localization of ATP‐citrate lyase in cholinergic nerve endings, and indicate that this enzyme is not a rate limiting step in the synthesis of the acetyl moiety of ACh in brain.