2.0 2012-05-31 14:08:05 -0600 2015-06-03 15:54:51 -0600 ECMDB06334 M2MDB000665 3-Dehydro-L-gulonate 3-Dehydro-L-gulonate is an intermediate in ascorbic acid degradation. It is a substrate for the enzyme 2,3-diketo-L-gulonate reductase. This enzyme catalyzes the reduction of 2,3-diketo-L-gulonate in the presence of NADH, to form 3-keto-L-gulonate. It participates in the reaction: 3-dehydro-L-gulonate + NAD(P)+ = (4R,5S)-4,5,6-trihydroxy-2,3-dioxohexanoate + NAD(P)H. Several pathways for the irreversible catabolism of ascorbate have been described. Facultatively aerobic bacteria such as Escherichia coli degrade L-ascorbate by different pathways under aerobic and anaerobic conditions. The anaerobic pathway begins with phosphorylation of ascorbate (mediated by a PTS-type transporter), while the aerobic pathway proceeds via 2,3-dioxo-L-gulonate. Both pathways produce D-xylulose 5-phosphate, a centeral metabolite that is fed into the pentose phosphate pathway. 3-Dehydro-L-gulonate 3-Dehydro-L-gulonic acid L-Xylo-hex-3-ulosonate L-Xylo-hex-3-ulosonic acid C6H10O7 194.1394 194.042652674 (2S,4R,5S)-2,4,5,6-tetrahydroxy-3-oxohexanoic acid 3-dehydro-L-gulonic acid OC[C@H](O)[C@@H](O)C(=O)[C@H](O)C(O)=O InChI=1S/C6H10O7/c7-1-2(8)3(9)4(10)5(11)6(12)13/h2-3,5,7-9,11H,1H2,(H,12,13)/t2-,3+,5-/m0/s1 WTAHRPBPWHCMHW-LWKDLAHASA-N Solid Cytosol logp -2.56 ALOGPS logs -0.27 ALOGPS solubility 1.05e+02 g/l ALOGPS logp -2.6 ChemAxon pka_strongest_acidic 3.16 ChemAxon pka_strongest_basic -3 ChemAxon iupac (2S,4R,5S)-2,4,5,6-tetrahydroxy-3-oxohexanoic acid ChemAxon average_mass 194.1394 ChemAxon mono_mass 194.042652674 ChemAxon smiles OC[C@H](O)[C@@H](O)C(=O)[C@H](O)C(O)=O ChemAxon formula C6H10O7 ChemAxon inchi InChI=1S/C6H10O7/c7-1-2(8)3(9)4(10)5(11)6(12)13/h2-3,5,7-9,11H,1H2,(H,12,13)/t2-,3+,5-/m0/s1 ChemAxon inchikey WTAHRPBPWHCMHW-LWKDLAHASA-N ChemAxon polar_surface_area 135.29 ChemAxon refractivity 37.58 ChemAxon polarizability 16.3 ChemAxon rotatable_bond_count 5 ChemAxon acceptor_count 7 ChemAxon donor_count 5 ChemAxon physiological_charge -1 ChemAxon formal_charge 0 ChemAxon Ascorbate and aldarate metabolism ec00053 Pentose and glucuronate interconversions ec00040 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 L-ascorbate degradation II (bacterial, aerobic) PWY-6961 Specdb::CMs 20889 Specdb::CMs 39002 Specdb::CMs 169797 Specdb::NmrOneD 150160 Specdb::NmrOneD 150161 Specdb::NmrOneD 150162 Specdb::NmrOneD 150163 Specdb::NmrOneD 150164 Specdb::NmrOneD 150165 Specdb::NmrOneD 150166 Specdb::NmrOneD 150167 Specdb::NmrOneD 150168 Specdb::NmrOneD 150169 Specdb::NmrOneD 150170 Specdb::NmrOneD 150171 Specdb::NmrOneD 150172 Specdb::NmrOneD 150173 Specdb::NmrOneD 150174 Specdb::NmrOneD 150175 Specdb::NmrOneD 150176 Specdb::NmrOneD 150177 Specdb::NmrOneD 150178 Specdb::NmrOneD 150179 Specdb::MsMs 26864 Specdb::MsMs 26865 Specdb::MsMs 26866 Specdb::MsMs 33422 Specdb::MsMs 33423 Specdb::MsMs 33424 Specdb::MsMs 2421678 Specdb::MsMs 2421679 Specdb::MsMs 2421680 Specdb::MsMs 2513450 Specdb::MsMs 2513451 Specdb::MsMs 2513452 HMDB06334 439273 388406 C00618 3-KETO-L-GULONATE Keseler, I. M., Collado-Vides, J., Santos-Zavaleta, A., Peralta-Gil, M., Gama-Castro, S., Muniz-Rascado, L., Bonavides-Martinez, C., Paley, S., Krummenacker, M., Altman, T., Kaipa, P., Spaulding, A., Pacheco, J., Latendresse, M., Fulcher, C., Sarker, M., Shearer, A. G., Mackie, A., Paulsen, I., Gunsalus, R. P., Karp, P. D. (2011). "EcoCyc: a comprehensive database of Escherichia coli biology." Nucleic Acids Res 39:D583-D590. 21097882 Kanehisa, M., Goto, S., Sato, Y., Furumichi, M., Tanabe, M. (2012). "KEGG for integration and interpretation of large-scale molecular data sets." Nucleic Acids Res 40:D109-D114. 22080510 2,3-diketo-L-gulonate reductase P37672 DLGD_ECOLI dlgD http://ecmdb.ca/proteins/P37672.xml L-xylulose/3-keto-L-gulonate kinase P37677 LYXK_ECOLI lyx http://ecmdb.ca/proteins/P37677.xml 2,3-Diketo-L-gulonate + Hydrogen ion + NADH > 3-Dehydro-L-gulonate + NAD R02637 RXN0-703 3-Dehydro-L-gulonate + Adenosine triphosphate > 3-Dehydro-L-gulonate 6-phosphate + ADP + Hydrogen ion R07127 RXN0-704 3-Dehydro-L-gulonate + NAD <> 2,3-Diketo-L-gulonate + NADH + Hydrogen ion R02637 3-Dehydro-L-gulonate + NADP <> 2,3-Diketo-L-gulonate + NADPH + Hydrogen ion R02639 3-Dehydro-L-gulonate + Adenosine triphosphate <> 3-Dehydro-L-gulonate 6-phosphate + ADP R07127 3-Dehydro-L-gulonate + NAD < Hydrogen ion + 2,3-Diketo-L-gulonate + NADH RXN0-703 3-Dehydro-L-gulonate + NAD(P)(+) > (4R,5S)-4,5,6-trihydroxy-2,3-dioxohexanoate + NAD(P)H Adenosine triphosphate + 3-Dehydro-L-gulonate > ADP + 3-Dehydro-L-gulonate 6-phosphate 3-Dehydro-L-gulonate + NAD + NADP <> 2,3-Diketo-L-gulonate + NADH + NADPH + Hydrogen ion R02637 R02639 3-Dehydro-L-gulonate + Adenosine triphosphate > 3-keto-L-gulonate 6-phosphate + Adenosine diphosphate + Hydrogen ion + 3-Keto-L-gulonate 6-phosphate + ADP PW_R002697 2,3-Diketo-L-gulonate + NADH + Hydrogen ion + 2,3-Diketo-L-gulonate > 3-Dehydro-L-gulonate + NAD PW_R002698