Author: Beeckmans, S.; Kanarek, L.
Description: By means of covalently immobilized fumarase and mitochondrial or cytoplasmic malate dehydrogenase we were able to detect physical interactions between different enzymes of the citric acid cycle (fumarase with malate dehydrogenase, malate dehydrogenase with citrate synthase and fumarase with citrate synthase) and between the enzymes of both mitochondrial and cytoplasmic halves of the aspartate-malate shuttle (aspartate amino-transferase and malate dehydrogenase). The interactions between fumarase and malate dehydrogenase were also investigated by immobilizing one enzyme indirectly through antibodies bound to Sepharose-protein A. Our results are consistent with a model in which maximally four molecules of malate dehydrogenase are bound to one fumarase molecule. This complex is able to bind either citrate synthase or aspartate aminotransferase. We propose that these enzymes bind alternatively, in order to allow the cell to perform citric acid cycle or shuttle reactions, according to its needs. The physiological meaning and implications on the regulation of metabolism of the existence of a large citric acid cycle/malate-aspartate shuttle multienzyme complex are discussed.
Subject headings: Animals; Antigen-Antibody Complex; Aspartate Aminotransferases/metabolism; Aspartic Acid/metabolism; Chickens; Citrate (si)-Synthase/metabolism; Citric Acid Cycle; Cytosol/enzymology; Fumarate Hydratase/metabolism; Immune Sera; Kinetics; Malate Dehydrogenase/metabolism; Malates/metabolism; Mitochondria, Heart/enzymology; Multienzyme Complexes/metabolism; Myocardium/enzymology; Oxo-Acid-Lyases/metabolism; Swine
Publication year: 1981
Journal or book title: European Journal of Biochemistry
Volume: 117
Issue: 3
Pages: 527-535
Find the full text : https://www.strategian.com/fulltext/Beeckmans1981.pdf
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Type: Journal Article
Serial number: 2894