Association between the α-ketoglutarate dehydrogenase complex and succinate thiokinase

Porpáczy, Zoltán; Sümegi, Balázs; Alkonyi, István

doi:10.1016/0167-4838(83)90249-2

Cited by 55 publications

(19 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Historically, metabolon studies initiated from the detection of aggregation of enzymes in vitro 31. This work was followed by in vitro enzymatic characterization using purified complexes and structural analysis including modelling approaches293033345354. However, it is very difficult to exclude the possibility of artefacts inducing protein aggregation in vitro because of the microenvironment of enzymes, which is significantly different from in vivo situation.…”

Section: Discussionmentioning

confidence: 99%

“…However, the potential of the constituent enzymes of the plant TCA cycle to interact is yet to be experimentally addressed. By contrast, the possibility of the TCA cycle operating as a metabolon has been much studied in mammalian and yeast systems293031323334353637, with the term ‘metabolon' even being coined for this pathway1. Binary interaction studies of the enzymes have also been provided using the bacterial-two-hybrid assay in Bacillus subtilis 38.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Protein-protein interactions and metabolite channelling in the plant tricarboxylic acid cycle

et al. 2017

View full text Add to dashboard Cite

Protein complexes of sequential metabolic enzymes, often termed metabolons, may permit direct channelling of metabolites between the enzymes, providing increased control over metabolic pathway fluxes. Experimental evidence supporting their existence in vivo remains fragmentary. In the present study, we test binary interactions of the proteins constituting the plant tricarboxylic acid (TCA) cycle. We integrate (semi-)quantitative results from affinity purification-mass spectrometry, split-luciferase and yeast-two-hybrid assays to generate a single reliability score for assessing protein–protein interactions. By this approach, we identify 158 interactions including those between catalytic subunits of sequential enzymes and between subunits of enzymes mediating non-adjacent reactions. We reveal channelling of citrate and fumarate in isolated potato mitochondria by isotope dilution experiments. These results provide evidence for a functional TCA cycle metabolon in plants, which we discuss in the context of contemporary understanding of this pathway in other kingdoms.

show abstract

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Protein-protein interactions and metabolite channelling in the plant tricarboxylic acid cycle

et al. 2017

View full text Add to dashboard Cite

show abstract

“…Regions that are conserved within a subunit type, but not between subunits, could be a reflection of interactions with other proteins. In this regard, there is evidence for complex formation between G-SCS and ␣-ketoglutarate dehydrogenase (28) and between SCS and nucleoside-diphosphate kinase (29,30).…”

Section: Figmentioning

confidence: 99%

Genetic Evidence for the Expression of ATP- and GTP-specific Succinyl-CoA Synthetases in Multicellular Eucaryotes

Johnson

Mehus

Tews

et al. 1998

Journal of Biological Chemistry

137

144

View full text Add to dashboard Cite

“…The term metabolon was introduced to describe such enzyme-enzyme complexes (3,4). Among the mitochondrial enzymes of the Krebs tricarboxylic acid cycle, interactions occur between six of eight sequential enzymes: fumarase with mitochondrial malate dehydrogenase (mMDH) 1 (5), mMDH with citrate synthase (CS) (6 -11), succinyl-CoA synthetase with ␣-ketoglutarate dehydrogenase complex (12), mitochondrial aconitase (mACO) with CS (13), NAD-dependent isocitrate dehydrogenase with mACO (14), and NAD-dependent isocitrate dehydrogenase with ␣-ketoglutarate dehydrogenase complex (15). Moreover, it has been shown that all of these enzymes bind to the inner surface of the mitochondrial inner membrane, whereas purified isozymes from other cellular compartments do not possess such binding abilities (13).…”

mentioning

confidence: 99%

Interaction between Citrate Synthase and Malate Dehydrogenase

Morgunov

Srere

1998

Journal of Biological Chemistry

113

View full text Add to dashboard Cite

The interactions between pig heart citrate synthase and mitochondrial malate dehydrogenase or cytosolic malate dehydrogenase were studied using the frontal analysis method of gel filtration and by precipitation in polyethylene glycol. This method showed that an interaction between citrate synthase and mitochondrial malate dehydrogenase occurred but no interaction between citrate synthase and cytosolic malate dehydrogenase. Channeling of oxaloacetate in the malate dehydrogenase and citrate synthase-coupled systems was tested using polyethylene glycol precipitates of citrate synthase and mitochondrial malate dehydrogenase, and citrate synthase and cytosolic malate dehydrogenase. The effectiveness of large amounts of aspartate aminotransferase and oxaloacetate decarboxylase, as competing enzymes for the intermediate oxaloacetate, was examined. Aspartate aminotransferase and oxaloacetate decarboxylase were less effective competitors for oxaloacetate when precipitated citrate synthase and mitochondrial malate dehydrogenase in polyethylene glycol was used at low ionic strength compared with free enzymes in the absence of polyethylene glycol or with a co-precipitate of citrate synthase and cytosolic malate dehydrogenase. Substrate channeling of oxaloacetate with citrate synthase-mitochondrial malate dehydrogenase precipitate was inefficient at high ionic strength. These effects could be explained through electrostatic interactions of mitochondrial but not cytosolic malate dehydrogenase with citrate synthase.In the last twenty years it has been demonstrated that sequential enzymes which operate within a metabolic pathway interact with each other to form highly organized complexes (1, 2). The term metabolon was introduced to describe such enzyme-enzyme complexes (3, 4). Among the mitochondrial enzymes of the Krebs tricarboxylic acid cycle, interactions occur between six of eight sequential enzymes: fumarase with mitochondrial malate dehydrogenase (mMDH) 1 (5), mMDH with citrate synthase (CS) (6 -11), succinyl-CoA synthetase with ␣-ketoglutarate dehydrogenase complex (12), mitochondrial aconitase (mACO) with CS (13), NAD-dependent isocitrate dehydrogenase with mACO (14), and NAD-dependent isocitrate dehydrogenase with ␣-ketoglutarate dehydrogenase complex (15). Moreover, it has been shown that all of these enzymes bind to the inner surface of the mitochondrial inner membrane, whereas purified isozymes from other cellular compartments do not possess such binding abilities (13). Organized enzyme complexes may have several kinetic advantages for the cell (16,17). One possible advantage is preventing intermediates from escaping into solution where they may be sequestered by other enzymes for use in different metabolic pathways. In other words, the close proximity of consecutive enzymes of a metabolic pathway may be used to increase the metabolic flow through this pathway, especially by channeling the substrate at reduced bulk substrate concentration.However, there are methodological problems in demonstrating the in vitro exis...

show abstract

Association between the α-ketoglutarate dehydrogenase complex and succinate thiokinase

Cited by 55 publications

References 18 publications

Protein-protein interactions and metabolite channelling in the plant tricarboxylic acid cycle

Protein-protein interactions and metabolite channelling in the plant tricarboxylic acid cycle

Genetic Evidence for the Expression of ATP- and GTP-specific Succinyl-CoA Synthetases in Multicellular Eucaryotes

Interaction between Citrate Synthase and Malate Dehydrogenase

Contact Info

Product

Resources

About