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discounted EARLY registration ends Dec 31, 2014
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discounted EARLY registration ends Dec 31, 2014
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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 Mon Dec 22, 2014, BIOCYC13A.