2.0 2012-08-09 09:16:15 -0600 2015-10-15 16:13:53 -0600 ECMDB21438 M2MDB001833 Ubiquinone-1 Ubiquinone-1 is a member of the chemical class known as Polyprenylbenzoquinones. These are compounds containing a polyisoprene chain attached to a quinone at the second ring position. Ubiquione-1 has just 1 isoprene unit. Normally in E. coli the active form of Ubiquinone has 8 isoprene units (Ubiquinone-8) and in humans it normally has 10. Ubiquinone-1 is a “failed” or incomplete version of Ubiquinone 8 that arises from conjugation by a shortened prenyl tail via 4-hydroxybenzoate polyprenyltransferase. Ubiquionone is involved in cellular respiration. It is fat-soluble and is therefore mobile in cellular membranes; it plays a unique role in the electron transport chain (ETC). In the inner bacterial membrane, electrons from NADH and succinate pass through the ETC to the oxygen, which is then reduced to water. The transfer of electrons through ETC results in the pumping of H+ across the membrane creating a proton gradient across the membrane, which is used by ATP synthase (located on the membrane) to generate ATP. 2,3-dimethoxy-5-methyl-6-(3-methylbut-2-enyl)cyclohexa-2,5-diene-1,4-dione A ubiquinone Coenzym Q coenzyme Q Coenzyme Q1 Coenzymes Q CoQ CoQ1 Koenzym Q Mitoquinones Q Q1 Ubichinon Ubiquinone Ubiquinone 5 Ubiquinone Q1 Ubiquinone(1) Ubiquinone-Q1 Ubiquinones Ubiquionone 1 C19H28O4 320.429 320.198759382 2,3-dimethoxy-5-methyl-6-(3-methylbut-2-en-1-yl)cyclohexa-2,5-diene-1,4-dione ubiquinone-1 727-81-1 COC1=C(O)C(C)=C(CC=C(C)CCC=C(C)C)C(O)=C1OC InChI=1S/C19H28O4/c1-12(2)8-7-9-13(3)10-11-15-14(4)16(20)18(22-5)19(23-6)17(15)21/h8,10,20-21H,7,9,11H2,1-6H3 RNUCUWWMTTWKAH-UHFFFAOYSA-N Solid Membrane logp 2.20 ALOGPS logs -3.02 ALOGPS solubility 2.39e-01 g/l ALOGPS logp 2.22 ChemAxon pka_strongest_basic -4.7 ChemAxon iupac 2,3-dimethoxy-5-methyl-6-(3-methylbut-2-en-1-yl)cyclohexa-2,5-diene-1,4-dione ChemAxon average_mass 320.429 ChemAxon mono_mass 320.198759382 ChemAxon smiles COC1=C(O)C(C)=C(CC=C(C)CCC=C(C)C)C(O)=C1OC ChemAxon formula C19H28O4 ChemAxon inchi InChI=1S/C19H28O4/c1-12(2)8-7-9-13(3)10-11-15-14(4)16(20)18(22-5)19(23-6)17(15)21/h8,10,20-21H,7,9,11H2,1-6H3 ChemAxon inchikey RNUCUWWMTTWKAH-UHFFFAOYSA-N ChemAxon polar_surface_area 52.6 ChemAxon refractivity 72.38 ChemAxon polarizability 26.94 ChemAxon rotatable_bond_count 4 ChemAxon acceptor_count 4 ChemAxon donor_count 0 ChemAxon physiological_charge 0 ChemAxon formal_charge 0 ChemAxon Pentose phosphate pathway ec00030 Oxidative phosphorylation The process of oxidative phosphorylation involves multiple interactions of ubiquinone with succinic acid, resulting in a fumaric acid and ubiquinol. Ubiquinone interacts with succinic acid through a succinate:quinone oxidoreductase resulting in a fumaric acid an ubiquinol. This enzyme has various cofactors, ferroheme b, 2FE-2S, FAD, and 3Fe-4S iron-sulfur cluster. Then 2 ubiquinol interact with oxygen and 4 hydrogen ion through a cytochrome bd-I terminal oxidase resulting in a 4 hydrogen ion transferred into the periplasmic space, 2 water returned into the cytoplasm and 2 ubiquinone, which stay in the inner membrane. The ubiquinone interacts with succinic acid through a succinate:quinone oxidoreductase resulting in a fumaric acid an ubiquinol. Then 2 ubiquinol interacts with oxygen and 4 hydrogen ion through a cytochrome bd-II terminal oxidase resulting in a 4 hydrogen ion transferred into the periplasmic space, 2 water returned into the cytoplasm and 2 ubiquinone, which stay in the inner membrane. The ubiquinone interacts with succinic acid through a succinate:quinone oxidoreductase resulting in a fumaric acid an ubiquinol. The 2 ubiquinol interact with oxygen and 8 hydrogen ion through a cytochrome bo terminal oxidase resulting in a 8 hydrogen ion transferred into the periplasmic space, 2 water returned into the cytoplasm and 2 ubiquinone, which stays in the inner membrane. The ubiquinone then interacts with 5 hydrogen ion through a NADH dependent ubiquinone oxidoreductase I resulting in NAD, hydrogen ion released into the periplasmic space and an ubiquinol. The ubiquinol is then processed reacting with oxygen, and 4 hydrogen through a ion cytochrome bd-I terminal oxidase resulting in 4 hydrogen ions released into the periplasmic space, 2 water molecules into the cytoplasm and 2 ubiquinones. The ubiquinone then interacts with 5 hydrogen ion through a NADH dependent ubiquinone oxidoreductase I resulting in NAD, hydrogen ion released into the periplasmic space and an ubiquinol. The 2 ubiquinol interact with oxygen and 8 hydrogen ion through a cytochrome bo terminal oxidase resulting in a 8 hydrogen ion transferred into the periplasmic space, 2 water returned into the cytoplasm and 2 ubiquinone, which stays in the inner membrane. PW000919 ec00190 Metabolic Pyrimidine metabolism The metabolism of pyrimidines begins with L-glutamine interacting with water molecule and a hydrogen carbonate through an ATP driven carbamoyl phosphate synthetase resulting in a hydrogen ion, an ADP, a phosphate, an L-glutamic acid and a carbamoyl phosphate. The latter compound interacts with an L-aspartic acid through a aspartate transcarbamylase resulting in a phosphate, a hydrogen ion and a N-carbamoyl-L-aspartate. The latter compound interacts with a hydrogen ion through a dihydroorotase resulting in the release of a water molecule and a 4,5-dihydroorotic acid. This compound interacts with an ubiquinone-1 through a dihydroorotate dehydrogenase, type 2 resulting in a release of an ubiquinol-1 and an orotic acid. The orotic acid then interacts with a phosphoribosyl pyrophosphate through a orotate phosphoribosyltransferase resulting in a pyrophosphate and an orotidylic acid. The latter compound then interacts with a hydrogen ion through an orotidine-5 '-phosphate decarboxylase, resulting in an release of carbon dioxide and an Uridine 5' monophosphate. The Uridine 5' monophosphate process to get phosphorylated by an ATP driven UMP kinase resulting in the release of an ADP and an Uridine 5--diphosphate. Uridine 5-diphosphate can be metabolized in multiple ways in order to produce a Deoxyuridine triphosphate. 1.-Uridine 5-diphosphate interacts with a reduced thioredoxin through a ribonucleoside diphosphate reductase 1 resulting in the release of a water molecule and an oxidized thioredoxin and an dUDP. The dUDP is then phosphorylated by an ATP through a nucleoside diphosphate kinase resulting in the release of an ADP and a DeoxyUridine triphosphate. 2.-Uridine 5-diphosphate interacts with a reduced NrdH glutaredoxin-like protein through a Ribonucleoside-diphosphate reductase 1 resulting in a release of a water molecule, an oxidized NrdH glutaredoxin-like protein and a dUDP. The dUDP is then phosphorylated by an ATP through a nucleoside diphosphate kinase resulting in the release of an ADP and a DeoxyUridine triphosphate. 3.-Uridine 5-diphosphate is phosphorylated by an ATP-driven nucleoside diphosphate kinase resulting in an ADP and an Uridinetriphosphate. The latter compound interacts with a reduced flavodoxin through ribonucleoside-triphosphate reductase resulting in the release of an oxidized flavodoxin, a water molecule and a Deoxyuridine triphosphate 4.-Uridine 5-diphosphate is phosphorylated by an ATP-driven nucleoside diphosphate kinase resulting in an ADP and an Uridinetriphosphate The uridine triphosphate interacts with a L-glutamine and a water molecule through an ATP driven CTP synthase resulting in an ADP, a phosphate, a hydrogen ion, an L-glutamic acid and a cytidine triphosphate. The cytidine triphosphate interacts with a reduced flavodoxin through a ribonucleoside-triphosphate reductase resulting in the release of a water molecule, an oxidized flavodoxin and a dCTP. The dCTP interacts with a water molecule and a hydrogen ion through a dCTP deaminase resulting in a release of an ammonium molecule and a Deoxyuridine triphosphate. 5.-Uridine 5-diphosphate is phosphorylated by an ATP-driven nucleoside diphosphate kinase resulting in an ADP and an Uridinetriphosphate The uridine triphosphate interacts with a L-glutamine and a water molecule through an ATP driven CTP synthase resulting in an ADP, a phosphate, a hydrogen ion, an L-glutamic acid and a cytidine triphosphate. The cytidine triphosphate then interacts spontaneously with a water molecule resulting in the release of a phosphate, a hydrogen ion and a CDP. The CDP then interacts with a reduced NrdH glutaredoxin-like protein through a ribonucleoside-diphosphate reductase 2 resulting in the release of a water molecule, an oxidized NrdH glutaredoxin-like protein and a dCDP. The dCDP is then phosphorylated through an ATP driven nucleoside diphosphate kinase resulting in an ADP and a dCTP. The dCTP interacts with a water molecule and a hydrogen ion through a dCTP deaminase resulting in a release of an ammonium molecule and a Deoxyuridine triphosphate. 6.-Uridine 5-diphosphate is phosphorylated by an ATP-driven nucleoside diphosphate kinase resulting in an ADP and an Uridinetriphosphate The uridine triphosphate interacts with a L-glutamine and a water molecule through an ATP driven CTP synthase resulting in an ADP, a phosphate, a hydrogen ion, an L-glutamic acid and a cytidine triphosphate. The cytidine triphosphate then interacts spontaneously with a water molecule resulting in the release of a phosphate, a hydrogen ion and a CDP. The CDP interacts with a reduced thioredoxin through a ribonucleoside diphosphate reductase 1 resulting in a release of a water molecule, an oxidized thioredoxin and a dCDP. The dCDP is then phosphorylated through an ATP driven nucleoside diphosphate kinase resulting in an ADP and a dCTP. The dCTP interacts with a water molecule and a hydrogen ion through a dCTP deaminase resulting in a release of an ammonium molecule and a Deoxyuridine triphosphate. The deoxyuridine triphosphate then interacts with a water molecule through a nucleoside triphosphate pyrophosphohydrolase resulting in a release of a hydrogen ion, a phosphate and a dUMP. The dUMP then interacts with a methenyltetrahydrofolate through a thymidylate synthase resulting in a dihydrofolic acid and a 5-thymidylic acid. Then 5-thymidylic acid is then phosphorylated through a nucleoside diphosphate kinase resulting in the release of an ADP and thymidine 5'-triphosphate. PW000942 ec00240 Metabolic TCA cycle The TCA pathway is a catabolic pathway of aerobic respiration. It generates energy and reducing power. It is the first step in generating precursors for biosynthesis. When acetate is the carbon source, citrate synthase is rate-limiting for the TCA cycle. Respiration is an ATP-generating process in which compounds act as electron donors through a chain of electron transfer to electron acceptors. Aerobic respiration uses oxygen as the final acceptor. Anaerobic respiration uses several organic compounds as acceptors such as fumarate, nitrate and hydrogen. During the chain of electron transfer, protons (H+) are transported outside the cytoplasmic membrane, generating a proton motive force. Upon passage of protons back into the cytoplasm, the PMF energy is captured as ATP, catalyzed by a multisubunit ATPase. The cycle can start from Acetyl-CoA interacting with Oxalacetic acid and water through a citrate synthase monomer resulting in a hydrogen ion, CoA and a Citric Acid. The latter compound is dehydrated by a Citrate hydro-lyase resulting in the release of water and a cis-Aconitic acid. This compound is then hydrated through a Citrate hydro-lyase resulting in a D-threo-Isocitric acid. This compound is decarboxylated by an NADP dependent Citrate dehydrogenase, resulting in a release of carbon dioxide and NADPH and Oxoglutaric acid. The oxoglutaric acid interacts with a Coenzyme A through a NAD driven 2-oxoglutarate dehydrogenase resulting in a release of carbon dioxide, an NADH and succinyl-CoA. The succinyl-CoA interacts with a phosphate and an ADP through a 2-oxoglutarate dehydrogenase resulting in a CoA, an ATP and Succinic Acid. Succinic acid interacts with a ubiquinone, in this case a ubiquinone 1 through a succinate:quinone oxidoreductase resulting in an ubiquinol, in this case a ubiquinol-1 and a fumaric acid. The fumaric acid interacts with water through a fumarase hydratase resulting in a L-Malic acid.This compound can either interact with quinone through a malate:quinone oxidoreductase resulting in a release of hydroquinone and oxalacetic acid, or it can react with an NAD through a malate dehydrogenase resulting in a hydrogen ion, NADH and Oxalacetic acid. PW000779 Metabolic glycerol metabolism Glycerol metabolism starts with glycerol is introduced into the cytoplasm through a glycerol channel GlpF Glycerol is then phosphorylated through an ATP mediated glycerol kinase resulting in a Glycerol 3-phosphate. This compound can also be obtained through a glycerophosphodiester reacting with water through a glycerophosphoryl diester phosphodiesterase or it can also be introduced into the cytoplasm through a glycerol-3-phosphate:phosphate antiporter. Glycerol 3-phosphate is then metabolized into a dihydroxyacetone phosphate in both aerobic or anaerobic conditions. In anaerobic conditions the metabolism is done through the reaction of glycerol 3-phosphate with a menaquinone mediated by a glycerol-3-phosphate dehydrogenase protein complex. In aerobic conditions, the metabolism is done through the reaction of glycerol 3-phosphate with ubiquinone mediated by a glycerol-3-phosphate dehydrogenase [NAD(P]+]. Dihydroxyacetone phosphate is then introduced into the fructose metabolism by turning a dihydroxyacetone into an isomer through a triosephosphate isomerase resulting in a D-glyceraldehyde 3-phosphate which in turn reacts with a phosphate through a NAD dependent Glyceraldehyde 3-phosphate dehydrogenase resulting in a glyceric acid 1,3-biphosphate. This compound is desphosphorylated by a phosphoglycerate kinase resulting in a 3-phosphoglyceric acid.This compound in turn can either react with a 2,3-bisphosphoglycerate-independent phosphoglycerate mutase or a 2,3-bisphosphoglycerate-independent phosphoglycerate mutase resulting in a 2-phospho-D-glyceric acid. This compound interacts with an enolase resulting in a phosphoenolpyruvic acid and water. Phosphoenolpyruvic acid can react either through a AMP driven phosphoenoylpyruvate synthase or a ADP driven pyruvate kinase protein complex resulting in a pyruvic acid. Pyruvic acid reacts with CoA through a NAD driven pyruvate dehydrogenase complex resulting in a carbon dioxide and a Acetyl-CoA which gets incorporated into the TCA cycle pathway. PW000914 Metabolic glycerol metabolism II Glycerol metabolism starts with glycerol is introduced into the cytoplasm through a glycerol channel GlpF Glycerol is then phosphorylated through an ATP mediated glycerol kinase resulting in a Glycerol 3-phosphate. This compound can also be obtained through sn-glycero-3-phosphocholine reacting with water through a glycerophosphoryl diester phosphodiesterase producing a benzyl alcohol, a hydrogen ion and a glycerol 3-phosphate or the campound can be introduced into the cytoplasm through a glycerol-3-phosphate:phosphate antiporter. Glycerol 3-phosphate is then metabolized into a dihydroxyacetone phosphate in both aerobic or anaerobic conditions. In anaerobic conditions the metabolism is done through the reaction of glycerol 3-phosphate with a menaquinone mediated by a glycerol-3-phosphate dehydrogenase protein complex. In aerobic conditions, the metabolism is done through the reaction of glycerol 3-phosphate with ubiquinone mediated by a glycerol-3-phosphate dehydrogenase [NAD(P]+]. Dihydroxyacetone phosphate is then introduced into the fructose metabolism by turning a dihydroxyacetone into an isomer through a triosephosphate isomerase resulting in a D-glyceraldehyde 3-phosphate which in turn reacts with a phosphate through a NAD dependent Glyceraldehyde 3-phosphate dehydrogenase resulting in a glyceric acid 1,3-biphosphate. This compound is desphosphorylated by a phosphoglycerate kinase resulting in a 3-phosphoglyceric acid.This compound in turn can either react with a 2,3-bisphosphoglycerate-independent phosphoglycerate mutase or a 2,3-bisphosphoglycerate-independent phosphoglycerate mutase resulting in a 2-phospho-D-glyceric acid. This compound interacts with an enolase resulting in a phosphoenolpyruvic acid and water. Phosphoenolpyruvic acid can react either through a AMP driven phosphoenoylpyruvate synthase or a ADP driven pyruvate kinase protein complex resulting in a pyruvic acid. Pyruvic acid reacts with CoA through a NAD driven pyruvate dehydrogenase complex resulting in a carbon dioxide and a Acetyl-CoA which gets incorporated into the TCA cycle pathway. PW000915 Metabolic glycerol metabolism III (sn-glycero-3-phosphoethanolamine) Glycerol metabolism starts with glycerol is introduced into the cytoplasm through a glycerol channel GlpF Glycerol is then phosphorylated through an ATP mediated glycerol kinase resulting in a Glycerol 3-phosphate. This compound can also be obtained through sn-glycero-3-phosphethanolamine reacting with water through a glycerophosphoryl diester phosphodiesterase producing a benzyl alcohol, a hydrogen ion and a glycerol 3-phosphate or the campound can be introduced into the cytoplasm through a glycerol-3-phosphate:phosphate antiporter. Glycerol 3-phosphate is then metabolized into a dihydroxyacetone phosphate in both aerobic or anaerobic conditions. In anaerobic conditions the metabolism is done through the reaction of glycerol 3-phosphate with a menaquinone mediated by a glycerol-3-phosphate dehydrogenase protein complex. In aerobic conditions, the metabolism is done through the reaction of glycerol 3-phosphate with ubiquinone mediated by a glycerol-3-phosphate dehydrogenase [NAD(P]+]. Dihydroxyacetone phosphate is then introduced into the fructose metabolism by turning a dihydroxyacetone into an isomer through a triosephosphate isomerase resulting in a D-glyceraldehyde 3-phosphate which in turn reacts with a phosphate through a NAD dependent Glyceraldehyde 3-phosphate dehydrogenase resulting in a glyceric acid 1,3-biphosphate. This compound is desphosphorylated by a phosphoglycerate kinase resulting in a 3-phosphoglyceric acid.This compound in turn can either react with a 2,3-bisphosphoglycerate-independent phosphoglycerate mutase or a 2,3-bisphosphoglycerate-independent phosphoglycerate mutase resulting in a 2-phospho-D-glyceric acid. This compound interacts with an enolase resulting in a phosphoenolpyruvic acid and water. Phosphoenolpyruvic acid can react either through a AMP driven phosphoenoylpyruvate synthase or a ADP driven pyruvate kinase protein complex resulting in a pyruvic acid. Pyruvic acid reacts with CoA through a NAD driven pyruvate dehydrogenase complex resulting in a carbon dioxide and a Acetyl-CoA which gets incorporated into the TCA cycle pathway. PW000916 Metabolic glycerol metabolism IV (glycerophosphoglycerol) Glycerol metabolism starts with glycerol is introduced into the cytoplasm through a glycerol channel GlpF Glycerol is then phosphorylated through an ATP mediated glycerol kinase resulting in a Glycerol 3-phosphate. This compound can also be obtained through glycerophosphoglycerol reacting with water through a glycerophosphoryl diester phosphodiesterase producing a benzyl alcohol, a hydrogen ion and a glycerol 3-phosphate or the campound can be introduced into the cytoplasm through a glycerol-3-phosphate:phosphate antiporter. Glycerol 3-phosphate is then metabolized into a dihydroxyacetone phosphate in both aerobic or anaerobic conditions. In anaerobic conditions the metabolism is done through the reaction of glycerol 3-phosphate with a menaquinone mediated by a glycerol-3-phosphate dehydrogenase protein complex. In aerobic conditions, the metabolism is done through the reaction of glycerol 3-phosphate with ubiquinone mediated by a glycerol-3-phosphate dehydrogenase [NAD(P]+]. Dihydroxyacetone phosphate is then introduced into the fructose metabolism by turning a dihydroxyacetone into an isomer through a triosephosphate isomerase resulting in a D-glyceraldehyde 3-phosphate which in turn reacts with a phosphate through a NAD dependent Glyceraldehyde 3-phosphate dehydrogenase resulting in a glyceric acid 1,3-biphosphate. This compound is desphosphorylated by a phosphoglycerate kinase resulting in a 3-phosphoglyceric acid.This compound in turn can either react with a 2,3-bisphosphoglycerate-independent phosphoglycerate mutase or a 2,3-bisphosphoglycerate-independent phosphoglycerate mutase resulting in a 2-phospho-D-glyceric acid. This compound interacts with an enolase resulting in a phosphoenolpyruvic acid and water. Phosphoenolpyruvic acid can react either through a AMP driven phosphoenoylpyruvate synthase or a ADP driven pyruvate kinase protein complex resulting in a pyruvic acid. Pyruvic acid reacts with CoA through a NAD driven pyruvate dehydrogenase complex resulting in a carbon dioxide and a Acetyl-CoA which gets incorporated into the TCA cycle pathway. PW000917 Metabolic glycerol metabolism V (glycerophosphoserine) Glycerol metabolism starts with glycerol is introduced into the cytoplasm through a glycerol channel GlpF Glycerol is then phosphorylated through an ATP mediated glycerol kinase resulting in a Glycerol 3-phosphate. This compound can also be obtained through glycerophosphoserine reacting with water through a glycerophosphoryl diester phosphodiesterase producing a benzyl alcohol, a hydrogen ion and a glycerol 3-phosphate or the campound can be introduced into the cytoplasm through a glycerol-3-phosphate:phosphate antiporter. Glycerol 3-phosphate is then metabolized into a dihydroxyacetone phosphate in both aerobic or anaerobic conditions. In anaerobic conditions the metabolism is done through the reaction of glycerol 3-phosphate with a menaquinone mediated by a glycerol-3-phosphate dehydrogenase protein complex. In aerobic conditions, the metabolism is done through the reaction of glycerol 3-phosphate with ubiquinone mediated by a glycerol-3-phosphate dehydrogenase [NAD(P]+]. Dihydroxyacetone phosphate is then introduced into the fructose metabolism by turning a dihydroxyacetone into an isomer through a triosephosphate isomerase resulting in a D-glyceraldehyde 3-phosphate which in turn reacts with a phosphate through a NAD dependent Glyceraldehyde 3-phosphate dehydrogenase resulting in a glyceric acid 1,3-biphosphate. This compound is desphosphorylated by a phosphoglycerate kinase resulting in a 3-phosphoglyceric acid.This compound in turn can either react with a 2,3-bisphosphoglycerate-independent phosphoglycerate mutase or a 2,3-bisphosphoglycerate-independent phosphoglycerate mutase resulting in a 2-phospho-D-glyceric acid. This compound interacts with an enolase resulting in a phosphoenolpyruvic acid and water. Phosphoenolpyruvic acid can react either through a AMP driven phosphoenoylpyruvate synthase or a ADP driven pyruvate kinase protein complex resulting in a pyruvic acid. Pyruvic acid reacts with CoA through a NAD driven pyruvate dehydrogenase complex resulting in a carbon dioxide and a Acetyl-CoA which gets incorporated into the TCA cycle pathway. PW000918 Metabolic proline metabolism The biosynthesis of L-proline in E. coli involves L-glutamic acid being phosphorylated through an ATP driven glutamate 5-kinase resulting in a L-glutamic acid 5-phosphate. This compound is then reduced through a NADPH driven gamma glutamyl phosphate reductase resulting in the release of a phosphate, a NADP and a L-glutamic gamma-semialdehyde. L-glutamic gamma-semialdehyde is dehydrated spontaneously, resulting in a release of water,hydrogen ion and 1-Pyrroline-5-carboxylic acid. The latter compound is reduced by an NADPH driven pyrroline-5-carboxylate reductase which is subsequently reduced to L-proline. L-proline works as a repressor of the pyrroline-5-carboxylate reductase enzyme and glutamate 5-kinase. In E. coli, the biosynthesis of L-proline from L-glutamate is governed by three genetic loci namely proB, proA and proC. The first reaction in the pathway is catalyzed by γ-glutamyl kinase, encoded by proB . The second reaction, NADPH-dependent reduction of γ-glutamyl phosphate to glutamate-5-semialdehyde, in the pathway is catalyzed by glutamate-5-semialdehyde dehydrogenase, encoded by proA . These two enzymes aggregate into a multimeric bi-functional enzyme complex known as γ-glutamyl kinase-GP-reductase multienzyme complex. It is believed that the complex formation serves to protect the highly labile glutamyl phosphate from the hostile nucleophilic and aqueous environment found in the cell . The final step in the pathway, the reduction of pyrroline 5-carboxylate to L-proline, is catalyzed by an NADPH-dependent pyrroline-5-carboxylate reductase encoded by proC . Proline is metabolized by being converted back to L-glutamate, which is further degraded to α-ketoglutarate, an intermediate of the TCA cycle. Curiously, L-glutamate, the obligate intermediate of the proline degradation pathway, cannot itself serve as a total source of carbon and energy for E. coli, because glutamate transport supplies exogenous glutamate at an inadequate rate. The proces by which proline is turned into L-glutamate starts with L-proline interacting with ubiquinone through a bifunctional protein putA resulting in an ubiquinol, a hydrogen ion and a 1-pyrroline-5-carboxylic acid. The latter compound is then hydrated spontaneously resulting in a L-glutamic gamma-semialdehyde. This compound is then processed by interacting with water through an NAD driven bifunctional protein putA resulting in a hydrogen ion, NADH and L-glutamic acid. 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Pyruvate dehydrogenase [cytochrome] P07003 POXB_ECOLI poxB http://ecmdb.ca/proteins/P07003.xml Succinate dehydrogenase iron-sulfur subunit P07014 DHSB_ECOLI sdhB http://ecmdb.ca/proteins/P07014.xml Bifunctional protein putA P09546 PUTA_ECOLI putA http://ecmdb.ca/proteins/P09546.xml Glycerol-3-phosphate dehydrogenase [NAD(P)+] P0A6S7 GPDA_ECOLI gpsA http://ecmdb.ca/proteins/P0A6S7.xml Dihydroorotate dehydrogenase P0A7E1 PYRD_ECOLI pyrD http://ecmdb.ca/proteins/P0A7E1.xml Succinate dehydrogenase flavoprotein subunit P0AC41 DHSA_ECOLI sdhA http://ecmdb.ca/proteins/P0AC41.xml Succinate dehydrogenase hydrophobic membrane anchor subunit P0AC44 DHSD_ECOLI sdhD http://ecmdb.ca/proteins/P0AC44.xml NADH-quinone oxidoreductase subunit A P0AFC3 NUOA_ECOLI nuoA http://ecmdb.ca/proteins/P0AFC3.xml NADH-quinone oxidoreductase subunit B P0AFC7 NUOB_ECOLI nuoB http://ecmdb.ca/proteins/P0AFC7.xml NADH-quinone oxidoreductase subunit E P0AFD1 NUOE_ECOLI nuoE http://ecmdb.ca/proteins/P0AFD1.xml NADH-quinone oxidoreductase subunit H P0AFD4 NUOH_ECOLI nuoH http://ecmdb.ca/proteins/P0AFD4.xml NADH-quinone oxidoreductase subunit I P0AFD6 NUOI_ECOLI nuoI http://ecmdb.ca/proteins/P0AFD6.xml NADH-quinone oxidoreductase subunit J P0AFE0 NUOJ_ECOLI nuoJ http://ecmdb.ca/proteins/P0AFE0.xml NADH-quinone oxidoreductase subunit K P0AFE4 NUOK_ECOLI nuoK http://ecmdb.ca/proteins/P0AFE4.xml NADH-quinone oxidoreductase subunit M P0AFE8 NUOM_ECOLI nuoM http://ecmdb.ca/proteins/P0AFE8.xml NADH-quinone oxidoreductase subunit N P0AFF0 NUON_ECOLI nuoN http://ecmdb.ca/proteins/P0AFF0.xml Quinoprotein glucose dehydrogenase P15877 DHG_ECOLI gcd http://ecmdb.ca/proteins/P15877.xml 3-demethylubiquinone-9 3-methyltransferase P17993 UBIG_ECOLI ubiG http://ecmdb.ca/proteins/P17993.xml NADH-quinone oxidoreductase subunit F P31979 NUOF_ECOLI nuoF http://ecmdb.ca/proteins/P31979.xml NADH-quinone oxidoreductase subunit C/D P33599 NUOCD_ECOLI nuoC http://ecmdb.ca/proteins/P33599.xml NADH-quinone oxidoreductase subunit G P33602 NUOG_ECOLI nuoG http://ecmdb.ca/proteins/P33602.xml NADH-quinone oxidoreductase subunit L P33607 NUOL_ECOLI nuoL http://ecmdb.ca/proteins/P33607.xml Succinate dehydrogenase cytochrome b556 subunit P69054 DHSC_ECOLI sdhC http://ecmdb.ca/proteins/P69054.xml Ubiquinol oxidase subunit 2 P0ABJ1 CYOA_ECOLI cyoA http://ecmdb.ca/proteins/P0ABJ1.xml Cytochrome o ubiquinol oxidase protein cyoD P0ABJ6 CYOD_ECOLI cyoD http://ecmdb.ca/proteins/P0ABJ6.xml Cytochrome bd-II oxidase subunit 2 P26458 APPB_ECOLI appB http://ecmdb.ca/proteins/P26458.xml Cytochrome bd-II oxidase subunit 1 P26459 APPC_ECOLI appC http://ecmdb.ca/proteins/P26459.xml Cytochrome d ubiquinol oxidase subunit 2 P0ABK2 CYDB_ECOLI cydB http://ecmdb.ca/proteins/P0ABK2.xml Ubiquinol oxidase subunit 1 P0ABI8 CYOB_ECOLI cyoB http://ecmdb.ca/proteins/P0ABI8.xml Cytochrome d ubiquinol oxidase subunit 1 P0ABJ9 CYDA_ECOLI cydA http://ecmdb.ca/proteins/P0ABJ9.xml Cytochrome o ubiquinol oxidase subunit 3 P0ABJ3 CYOC_ECOLI cyoC http://ecmdb.ca/proteins/P0ABJ3.xml Cytochrome bd-I ubiquinol oxidase subunit X P56100 CYDX_ECOLI cydX http://ecmdb.ca/proteins/P56100.xml Ubiquinol-8 + Acceptor <> Ubiquinone-1 + Reduced acceptor R02166 Pyruvic acid + Ubiquinone-1 + Water <> Acetic acid + Ubiquinol-8 + Carbon dioxide R03145 D-Glucose + Ubiquinone-1 <> Gluconolactone + Ubiquinol-8 R06620 2-Polyprenyl-3-methyl-5-hydroxy-6-methoxy-1,4-benzoquinone + S-Adenosylmethionine <> Ubiquinone-1 + S-Adenosylhomocysteine R08781 NADH + Ubiquinone-1 <> NAD + Ubiquinol-8 R02163 Succinic acid + Ubiquinone-1 > Ubiquinol-1 + Fumaric acid PW_R002619 L-Proline + Ubiquinone-1 + L-Proline > Hydrogen ion + Ubiquinol-1 + 1-Pyrroline-5-carboxylic acid + L-D-1-Pyrroline-5-carboxylic acid PW_R002720 Glycerol 3-phosphate + Ubiquinone-1 > Dihydroxyacetone phosphate + Ubiquinol-1 PW_R003441 4,5-Dihydroorotic acid + Ubiquinone-1 + 4,5-Dihydroorotic acid > Ubiquinol-1 + Orotic acid PW_R003528 2 Ubiquinol-1 + Oxygen + 4 Hydrogen ion >2 Ubiquinone-1 +2 Water +4 Hydrogen ion PW_RCT000140 Oxygen + 8 Hydrogen ion + 2 Ubiquinol-1 >2 Water +8 Hydrogen ion +2 Ubiquinone-1 PW_RCT000142 NADH + 5 Hydrogen ion + Ubiquinone-1 > Hydrogen ion + NAD + Ubiquinol-1 PW_RCT000143 D-Glucose + Ubiquinone-1 <> Gluconolactone + Ubiquinol-8 Ubiquinol-8 + Acceptor <> Ubiquinone-1 + Reduced acceptor NADH + Ubiquinone-1 <> NAD + Ubiquinol-8 Pyruvic acid + Ubiquinone-1 + Water <> Acetic acid + Ubiquinol-8 + Carbon dioxide D-Glucose + Ubiquinone-1 <> Gluconolactone + Ubiquinol-8 Ubiquinol-8 + Acceptor <> Ubiquinone-1 + Reduced acceptor Ubiquinol-8 + Acceptor <> Ubiquinone-1 + Reduced acceptor Ubiquinol-8 + Acceptor <> Ubiquinone-1 + Reduced acceptor Ubiquinol-8 + Acceptor <> Ubiquinone-1 + Reduced acceptor Ubiquinol-8 + Acceptor <> Ubiquinone-1 + Reduced acceptor Ubiquinol-8 + Acceptor <> Ubiquinone-1 + Reduced acceptor Pyruvic acid + Ubiquinone-1 + Water <> Acetic acid + Ubiquinol-8 + Carbon dioxide