Open AccessCitrate Synthesis in Intact Rat‐Liver Mitochondria Is Irreversible
Author(s) -
GREKSAK Miloslav,
LOPESCARDOZO Matthijs,
BERGH Simon G.
Publication year - 1982
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1982.tb05897.x
Subject(s) - malonate , citrate synthase , citric acid cycle , mitochondrion , chemistry , carnitine , ketone bodies , biochemistry , metabolism , enzyme
Rat‐liver mitochondria were incubated with [1,5‐ 14 C]citrate in the presence of fluorocitrate to block its oxidation in the Krebs cycle. The reaction products were analysed enzymatically and by anion‐exchange chromatography. Incorporation of 14 C into acetyl‐ l ‐carnitine or ketone bodies via a backward action of citrate synthase was not observed. The optimal rate of citrate synthesis from pyruvate and malate in the presence of fluorocitrate was 15 nmol. mg −1 . min −1 . In the absence of fluorocitrate, but in the presence of malonate, citrate was oxidized to succinate at a rate of 4 nmol . mg −1 . min −1 . We conclude that the synthesis of citrate by intact rat liver mitochondria is an irreversible process. The possible mechanism underlying this phenomenon and the consequence for metabolic regulation are discussed.