Succinyl coenzyme A synthetase

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Succinyl coenzyme A synthetase (succinate thiokinase) catalyzes the formation of succinate and coenzyme-A, a 4-carbon metabolite, from succinyl-CoA.

Contents 1 Reaction 2 Isoforms 3 Structure 4 References 5 External links

[edit] Reaction

Succinyl-CoA synthetase catalyzes a reversible step in the citric acid cycle, which involves the substrate-level phosphorylation of GDP.

succinyl-CoA

succinate

[edit] Isoforms

Johnson et al. describe two isoforms of succinyl-CoA synthetase in mammals, one that specifically uses ATP for synthesis, and one that utilizes GTP. ^[1]

• EC 6.2.1.5 - ADP-forming - SUCLA2
• EC 6.2.1.4 - GDP-forming - SUCLG1, SUCLG2

The GTP form is the one more commonly used in the human citric acid cycle.^{[citation needed]}

[edit] Structure

The crystal structure of Succinyl-CoA synthetase alpha subunit (ATP-binding isoform) was determined by Joyce et al. to a resolution of 2.10 A, with PDB code 1CQJ. [1].^[2]

[edit] References

1. ^ Johnson JD, Mehus JG, Tews K, Milavetz BI, Lambeth DO (1998). "Genetic evidence for the expression of ATP- and GTP-specific succinyl-CoA synthetases in multicellular eucaryotes". J Biol Chem 273 (42): 27580–6. doi:10.1074/jbc.273.42.27580. 
2. ^ Joyce, M. A., Fraser, M. E., James, M. N. G., Bridger, W. A., and Wolodko, W. T. (2000) Biochemistry 39, 17-25

[edit] External links

• MeSH Succinyl+Coenzyme+A+Synthetases

v • d • e Enzymes: ligases (EC 6) 6.1 - Carbon-Oxygen Aminoacyl tRNA synthetase 6.2 - Carbon-Sulfur Succinyl coenzyme A synthetase - Acetyl Co-A synthetase - Long fatty acyl CoA synthetase 6.3 - Carbon-Nitrogen Glutamine synthetase - Ubiquitin ligase (Von Hippel-Lindau tumor suppressor, UBE3A, Mdm2, Anaphase-promoting complex) - Glutathione synthetase - CTP synthase - Adenylosuccinate synthase - Argininosuccinate synthetase - Holocarboxylase synthetase - GMP synthase - Asparagine synthetase - Carbamoyl phosphate synthetase (I, II) - Gamma-glutamylcysteine synthetase 6.4 - Carbon-Carbon Carbon-carbon ligases 6.5 - Phosphoric Ester DNA ligase

v • d • e Metabolism: Citric acid cycle enzymes Cycle Citrate synthase - Aconitase - Isocitrate dehydrogenase - Oxoglutarate dehydrogenase - Succinyl CoA synthetase Succinate dehydrogenase (SDHA) - Fumarase - Malate dehydrogenase Anaplerotic to acetyl-CoA: Pyruvate dehydrogenase complex (regulated by Pyruvate dehydrogenase kinase and Pyruvate dehydrogenase phosphatase) to ketoglutaric acid: Glutamate dehydrogenase to succinyl-CoA: Methylmalonyl-CoA mutase to oxaloacetate: Pyruvate carboxylase - Aspartate transaminase

v • d • e Mitochondrial enzymes and transporters Outer membrane fatty acid degradation (Carnitine palmitoyltransferase I, Long fatty acyl CoA synthetase) tryptophan metabolism (Kynureninase) monoamine neurotransmitter metabolism (Monoamine oxidase) Intermembrane space Adenylate kinase - Creatine kinase Inner membrane oxidative phosphorylation (Coenzyme Q - cytochrome c reductase, Cytochrome c, NADH dehydrogenase, Succinate dehydrogenase) pyrimidine metabolism (Dihydroorotate dehydrogenase) mitochondrial shuttle (Malate-aspartate shuttle, Glycerol phosphate shuttle) other (Glutamate aspartate transporter, Glycerol-3-phosphate dehydrogenase, ATP synthase, Carnitine palmitoyltransferase II) Matrix citric acid cycle (Citrate synthase, Aconitase, Isocitrate dehydrogenase, Oxoglutarate dehydrogenase, Succinyl coenzyme A synthetase, Fumarase, Malate dehydrogenase) anaplerotic reactions (Aspartate transaminase, Glutamate dehydrogenase, Pyruvate dehydrogenase complex) urea cycle (Carbamoyl phosphate synthetase I, Ornithine transcarbamylase, N-Acetylglutamate synthase) alcohol metabolism (ALDH2) Other/to be sorted Cholesterol side-chain cleavage enzyme Mitochondrial DNA Complex I (7 units) - Complex III (1 unit) - Complex IV (3 units) - ATP synthase (2 units)