Metabolic Modeling Tutorial
discounted EARLY registration ends Dec 31, 2014
Metabolic Modeling Tutorial
discounted EARLY registration ends Dec 31, 2014
Metabolic Modeling Tutorial
discounted EARLY registration ends Dec 31, 2014
Metabolic Modeling Tutorial
discounted EARLY registration ends Dec 31, 2014
Metabolic Modeling Tutorial
discounted EARLY registration ends Dec 31, 2014
twitter

MetaCyc Enzyme: L-sorbose dehydrogenase / L-sorbosone dehydrogenase

Species: Ketogulonicigenium vulgare DSM 4025

Subunit composition of L-sorbose dehydrogenase / L-sorbosone dehydrogenase = [L-sorbose/L-sorbosone dehydrogenase 64.5 kD subunit][L-sorbose/L-sorbosone dehydrogenase 62.5 kD subunit]

Summary:
L-sorbose dehydrogenase / L-sorbosone dehydrogenase from Ketogulonicigenium vulgare DSM 4025 (previously referred to as Gluconobacter oxydans DSM 4025) [Asakura99] has been proposed to catalyze the first two steps of L-ascorbate biosynthesis in this organism (see pathway L-ascorbate biosynthesis III). It has a broad substrate specificity [Asakura99].

Both subunits had an approximate isoelectric point of 4.4 [Asakura99]. The relative molecular mass of native L-sorbose/L-sorbosone dehydrogenase was determined by gel filtration chromatography [Asakura99].

Locations: cytosol

Molecular Weight: 135 kD (experimental) [Asakura99 ]

Gene-Reaction Schematic: ?

GO Terms:

Cellular Component: GO:0005829 - cytosol [Asakura99]

Credits:
Created 13-Jun-2007 by Fulcher CA , SRI International


Enzymatic reaction of: L-sorbose dehydrogenase

EC Number: 1.1.99.32

keto-L-sorbose + an oxidized electron acceptor <=> L-sorbosone + a reduced electron acceptor

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the Enzyme Commission system.

The reaction is favored in the direction shown.

In Pathways: L-ascorbate biosynthesis III , 2-keto-L-gulonate biosynthesis

Kinetic Parameters:

Substrate
Km (μM)
Citations
keto-L-sorbose
230000.0
[Asakura99]


Enzymatic reaction of: L-sorbosone dehydrogenase

EC Number: 1.1.1.-

L-sorbosone 2,6-lactone + an oxidized electron acceptor + H2O <=> 2-keto-L-gulonate + a reduced electron acceptor + H+

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction in which it was curated.

The reaction is favored in the direction shown.

Alternative Substrates for L-sorbosone 2,6-lactone: propanal [Asakura99 ] , 2-butanol [Asakura99 ] , isopropanol [Asakura99 ] , heptanol [Asakura99 ] , hexanol [Asakura99 ] , n-pentanol [Asakura99 ] , n-butanol [Asakura99 ] , n-propanol [Asakura99 ] , ethanol [Asakura99 ] , D-glyceraldehyde [Asakura99 ] , D-fructose [Asakura99 ] , D-mannitol [Asakura99 ] , D-glucose [Asakura99 ] , L-sorbosone [Asakura99 ] , sorbose [Asakura99 ]

In Pathways: 2-keto-L-gulonate biosynthesis

Summary:
L-sorbose/L-sorbosone dehydrogenase was assayed using a dye-linked spectrophotometric assay with oxidized DCPIP (DCIP) as electron acceptor. It was shown to have a broad substrate specificity for aldehyde and alcohol compounds (as shown here) which were oxidized to their corresponding carboxylic acids and aldehydes. Methanol, however, was not a substrate. In addition, the polymers PEG 1000, PEG 4000, PEG 6000 and polyvinylalcohol were substrates. Although some metal ions inhibited activity, Mg2+ and Ca2+ did not. Experiments suggested that cytochrome c is the physiological electron acceptor in this organism. [Asakura99].

Cofactors or Prosthetic Groups: pyrroloquinoline quinone [Asakura99]

Inhibitors (Unknown Mechanism): Fe2+ [Asakura99] , Zn2+ [Asakura99] , Fe3+ [Asakura99] , Co2+ [Asakura99] , Ni2+ [Asakura99] , Cu2+ [Asakura99] , Mn2+ [Asakura99] , EDTA [Asakura99] , EGTA [Asakura99] , iodoacetate [Asakura99] , N-ethylmaleimide [Asakura99] , hydroxylamine [Asakura99]

T(opt): 30-40 °C [Asakura99]

pH(opt): 7-9 [Asakura99]


Subunit of L-sorbose dehydrogenase / L-sorbosone dehydrogenase: L-sorbose/L-sorbosone dehydrogenase 64.5 kD subunit

Molecular Weight: 64.5 kD (experimental) [Asakura99]


Subunit of L-sorbose dehydrogenase / L-sorbosone dehydrogenase: L-sorbose/L-sorbosone dehydrogenase 62.5 kD subunit

Molecular Weight: 62.5 kD (experimental) [Asakura99]

Summary:
The relative molecular mass of the subunits was determined by SDS-PAGE [Asakura99].


References

Asakura99: Asakura A, Hoshino T (1999). "Isolation and Characterization of a New Quinoprotein Dehydrogenase, L-Sorbose/L-Sorbosone Dehydrogenase." Biosci. Biotechnol. Biochem., 63 (1), 46-53.

Miyazaki06: Miyazaki T, Sugisawa T, Hoshino T (2006). "Pyrroloquinoline quinone-dependent dehydrogenases from Ketogulonicigenium vulgare catalyze the direct conversion of L-sorbosone to L-ascorbic acid." Appl Environ Microbiol 72(2);1487-95. PMID: 16461703


Report Errors or Provide Feedback
Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
Page generated by SRI International Pathway Tools version 18.5 on Sun Nov 23, 2014, biocyc13.