2.02012-05-31 14:36:25 -06002015-09-17 15:41:58 -0600ECMDB20271M2MDB0011133-Keto-L-gulonate 6-phosphate3-keto-L-gulonate 6-phosphate is a member of the chemical class known as Medium-chain Keto Acids and Derivatives. These are keto acids with a 6 to 12 carbon atoms long side chain. 3-Dehydro-L-gulonate-6-phosphate3-dehydro-L-Gulonic acid-6-phosphoric acid3-Keto-L-gulonate 6-P3-Keto-L-gulonate-6-phosphate3-Keto-L-gulonic acid 6-P3-Keto-L-gulonic acid 6-phosphate3-keto-L-Gulonic acid 6-phosphoric acid3-keto-L-Gulonic acid-6-phosphoric acidC6H9O10P272.103271.9944306482,4,5-trihydroxy-3-oxo-6-(phosphonooxy)hexanoic acid2,4,5-trihydroxy-3-oxo-6-(phosphonooxy)hexanoic acidOC(COP([O-])([O-])=O)C(O)C(=O)C(O)C(O)=OInChI=1S/C6H11O10P/c7-2(1-16-17(13,14)15)3(8)4(9)5(10)6(11)12/h2-3,5,7-8,10H,1H2,(H,11,12)(H2,13,14,15)/p-2BDUIIKXSXFDPEC-UHFFFAOYSA-LCytoplasmPeriplasmlogp-2.13logs-1.22solubility1.64e+01 g/llogp-2.8pka_strongest_acidic1.47pka_strongest_basic-3.6iupac2,4,5-trihydroxy-3-oxo-6-(phosphonooxy)hexanoic acidaverage_mass272.103mono_mass271.994430648smilesOC(COP([O-])([O-])=O)C(O)C(=O)C(O)C(O)=OformulaC6H9O10PinchiInChI=1S/C6H11O10P/c7-2(1-16-17(13,14)15)3(8)4(9)5(10)6(11)12/h2-3,5,7-8,10H,1H2,(H,11,12)(H2,13,14,15)/p-2inchikeyBDUIIKXSXFDPEC-UHFFFAOYSA-Lpolar_surface_area181.82refractivity48.45polarizability20.86rotatable_bond_count7acceptor_count9donor_count6physiological_charge-3formal_charge0Ascorbate metabolismE. 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.PW000793MetabolicL-ascorbate degradation II (bacterial, aerobic)PWY-6961L-ascorbate degradation I (bacterial, anaerobic)PWY0-301Specdb::MsMs23000Specdb::MsMs23001Specdb::MsMs23002Specdb::MsMs29798Specdb::MsMs29799Specdb::MsMs29800393384CPD-2343Keseler, 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-D590.21097882van der Werf, M. J., Overkamp, K. M., Muilwijk, B., Coulier, L., Hankemeier, T. (2007). "Microbial metabolomics: toward a platform with full metabolome coverage." Anal Biochem 370:17-25.17765195L-xylulose/3-keto-L-gulonate kinaseP37677LYXK_ECOLIlyxhttp://ecmdb.ca/proteins/P37677.xml3-keto-L-gulonate-6-phosphate decarboxylase sgbHP37678SGBH_ECOLIsgbHhttp://ecmdb.ca/proteins/P37678.xml3-keto-L-gulonate-6-phosphate decarboxylase ulaDP39304ULAD_ECOLIulaDhttp://ecmdb.ca/proteins/P39304.xmlProbable L-ascorbate-6-phosphate lactonase ulaGP39300ULAG_ECOLIulaGhttp://ecmdb.ca/proteins/P39300.xmlL-ascorbate 6-phosphate + Water + L-Ascorbate 6-phosphate > 3-keto-L-gulonate 6-phosphate + 3-Keto-L-gulonate 6-phosphatePW_R0026963-Dehydro-L-gulonate + Adenosine triphosphate > 3-keto-L-gulonate 6-phosphate + Adenosine diphosphate + Hydrogen ion + 3-Keto-L-gulonate 6-phosphate + ADPPW_R0026973-keto-L-gulonate 6-phosphate + Hydrogen ion + 3-Keto-L-gulonate 6-phosphate > Xylulose 5-phosphate + Carbon dioxide + Xylulose 5-phosphatePW_R0027033-keto-L-gulonate 6-phosphate + Hydrogen ion + 3-Keto-L-gulonate 6-phosphate > L-xylulose -5-phosphate + Carbon dioxide + L-Xylulose 5-phosphatePW_R0027123-keto-L-gulonate 6-phosphate + 3-Keto-L-gulonate 6-phosphate > L-xylulose -5-phosphate + L-Xylulose 5-phosphatePW_R002711