2.0 2015-09-08 17:48:53 -0600 2015-09-08 17:48:53 -0600 ECMDB24062 M2MDB006179 Dehydroascorbic acid Dehydroascorbate C6H6O6 174.1082 174.016437924 (5R)-5-[(1R)-1,2-dihydroxyethyl]oxolane-2,3,4-trione (5R)-5-[(1R)-1,2-dihydroxyethyl]oxolane-2,3,4-trione [H][C@@]1(OC(=O)C(=O)C1=O)[C@H](O)CO InChI=1S/C6H6O6/c7-1-2(8)5-3(9)4(10)6(11)12-5/h2,5,7-8H,1H2/t2-,5-/m1/s1 SBJKKFFYIZUCET-DUZGATOHSA-N logp -1.17 ALOGPS logs 0.04 ALOGPS solubility 1.90e+02 g/l ALOGPS logp -0.67 ChemAxon pka_strongest_acidic 1.56 ChemAxon pka_strongest_basic -3 ChemAxon iupac (5R)-5-[(1R)-1,2-dihydroxyethyl]oxolane-2,3,4-trione ChemAxon average_mass 174.1082 ChemAxon mono_mass 174.016437924 ChemAxon smiles [H][C@@]1(OC(=O)C(=O)C1=O)[C@H](O)CO ChemAxon formula C6H6O6 ChemAxon inchi InChI=1S/C6H6O6/c7-1-2(8)5-3(9)4(10)6(11)12-5/h2,5,7-8H,1H2/t2-,5-/m1/s1 ChemAxon inchikey SBJKKFFYIZUCET-DUZGATOHSA-N ChemAxon polar_surface_area 100.9 ChemAxon refractivity 33.55 ChemAxon polarizability 14.02 ChemAxon rotatable_bond_count 2 ChemAxon acceptor_count 5 ChemAxon donor_count 2 ChemAxon physiological_charge -1 ChemAxon formal_charge 0 ChemAxon Ascorbate metabolism E. coli is able to utilize L-ascorbate (vitamin C) as the sole source of carbon under anaerobic and aerobic conditions. Ascorbic acid in the cytoplasm is processed through a spontaneous reaction with a hydrogen ion and hydrogen peroxide, producing water, dehydroascorbic acid and ascorbic acid. Dehydroascorbic acid reacts with water spontaneously producing an isomer, dehydroascorbate (bicyclic form). The compound then loses a hydrogen ion resulting in a 2,3-Diketo-L-gulonate. This compound is then reduced through a NADH dependent 2,3 diketo-L-gulonate reductase, releasing a NAD and 3-Dehydro-L-gulonate.This compound is phosphorylated through an ATP mediated L-xylulose/3-keto-L-gulonate kinase resulting in an ADP, hydrogen ion and a 3-Keto-L-gulonate 6 phosphate. L-ascorbate can also be imported and converted to L-ascorbate-6-phosphate by the L-ascorbate PTS transporter. L-ascorbate-6-phosphate reacts with a probable L-ascorbate-6-phosphate lactonase ulaG, resulting in a 3-keto-L-gulonate 6-phosphate. The compound 3-keto-L-gulonate 6-phosphate can be processed aerobically or anaerobically. Aerobic: 3-keto-L-gulonate 6-phosphate is decarboxylated by a 3-keto-L-gulonate-6-phosphate decarboxylase ulaD, releasing carbon dioxide and L-xylulose-5-phosphate. This compound in turn is changed into an isomer by L-ribulose-5-phosphate 3-epimerase ulaE, resulting in L-ribulose 5-phosphate. This compound again changes into a different isomer through a L-ribulose-5-phosphate 4-epimerase ulaF resulting in Xylulose 5-phosphate. This compound can then be part of the pentose phosphate pathway. Anaerobic: 3-keto-L-gulonate 6-phosphate is decarboxylated by 3-keto-L-gulonate 6-phosphate decarboxylase sgbH, releasing carbon dioxide and L-xylulose-5-phosphate. This compound in turn is changed into an isomer by predicted L-xylulose 5-phosphate 3-epimerase, resulting in L-ribulose 5-phosphate. This compound again changes into a different isomer through a L-ribulose-5-phosphate 4-epimerase resulting in Xylulose 5-phosphate. This compound can then be part of the pentose phosphate pathway. Expression of the ula regulon is regulated by the L-ascorbate 6-phosphate-binding repressor UlaR and by cAMP-CRP. Under aerobic conditions, metabolism of L-ascorbate is hindered by the special reactivity and toxicity of this compound in the presence of oxygen. PW000793 Metabolic Specdb::CMs 12979 Specdb::CMs 37999 Specdb::NmrOneD 1674 Specdb::MsMs 1497 Specdb::MsMs 294517 Specdb::MsMs 294518 Specdb::MsMs 294519 Specdb::MsMs 335260 Specdb::MsMs 335261 Specdb::MsMs 335262 Specdb::NmrTwoD 1615