2.0 2012-08-09 09:25:32 -0600 2015-09-17 16:24:40 -0600 ECMDB21575 M2MDB001969 Ubiquinol-2 Ubiquinol-2 is a member of the chemical class known as Polyprenylbenzoquinols. They are reduced forms of polyprenylbenzoquinines (ubiquinones). These are compounds containing a polyisoprene chain attached to a quinol at the second ring position. Ubiquiol-2 has just 2 isoprene units. Normally in E. coli the active form of Ubiquinol has 8 isoprene units (Ubiquinol-8) and in humans it normally has 10. Ubiquinol-2 is a “failed” or incomplete version of Ubiquinol 8 that arises from conjugation by a shortened prenyl tail via 4-hydroxybenzoate polyprenyltransferase. Coenzyme Q(n) exists in three redox states, fully oxidized (ubiquinone), partially reduced (semiquinones or ubisemiquinones), and fully reduced (ubiquinols). The redox functions of ubiquinol in cellular energy production and antioxidant protection are based on the ability to exchange two electrons in a redox cycle between ubiquinol (reduced) and the ubiquinone (oxidized) form. Ubiquionols are important in cellular respiration. They are fat-soluble and therefore mobile in cellular membranes; they play 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. Not Available (C5H8)nC14H20O4 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/b13-10+ RNUCUWWMTTWKAH-JLHYYAGUSA-N Membrane logp 4.41 ALOGPS logs -4.41 ALOGPS solubility 1.25e-02 g/l ALOGPS formula (C5H8)nC14H20O4 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/b13-10+ ChemAxon inchikey RNUCUWWMTTWKAH-JLHYYAGUSA-N ChemAxon formal_charge 0 ChemAxon TCA cycle (ubiquinol-2) 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 2 through a succinate:quinone oxidoreductase resulting in an ubiquinol, in this case a ubiquinol-2 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. PW001002 Metabolic Specdb::CMs 63141 Specdb::NmrOneD 267148 Specdb::NmrOneD 267149 Specdb::NmrOneD 267150 Specdb::NmrOneD 267151 Specdb::NmrOneD 267152 Specdb::NmrOneD 267153 Specdb::NmrOneD 267154 Specdb::NmrOneD 267155 Specdb::NmrOneD 267156 Specdb::NmrOneD 267157 Specdb::NmrOneD 267158 Specdb::NmrOneD 267159 Specdb::NmrOneD 267160 Specdb::NmrOneD 267161 Specdb::NmrOneD 267162 Specdb::NmrOneD 267163 Specdb::NmrOneD 267164 Specdb::NmrOneD 267165 Specdb::NmrOneD 267166 Specdb::NmrOneD 267167 Specdb::MsMs 1307410 Specdb::MsMs 1307411 Specdb::MsMs 1307412 Specdb::MsMs 1421920 Specdb::MsMs 1421921 Specdb::MsMs 1421922 Specdb::MsMs 2309811 Specdb::MsMs 2309812 Specdb::MsMs 2309813 Specdb::MsMs 2655344 Specdb::MsMs 2655345 Specdb::MsMs 2655346 5280344 C00390 Winder, C. L., Dunn, W. B., Schuler, S., Broadhurst, D., Jarvis, R., Stephens, G. M., Goodacre, R. (2008). "Global metabolic profiling of Escherichia coli cultures: an evaluation of methods for quenching and extraction of intracellular metabolites." Anal Chem 80:2939-2948. 18331064 Succinate dehydrogenase iron-sulfur subunit P07014 DHSB_ECOLI sdhB http://ecmdb.ca/proteins/P07014.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 Succinate dehydrogenase cytochrome b556 subunit P69054 DHSC_ECOLI sdhC http://ecmdb.ca/proteins/P69054.xml Succinic acid + Ubiquinone-2 > Fumaric acid + Ubiquinol-2 PW_R003745