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discounted EARLY registration ends Dec 31, 2014
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MetaCyc Enzyme: D-sorbitol dehydrogenase

Species: Malus domestica

Subunit composition of D-sorbitol dehydrogenase = [sorbitol dehydrogenase subunit]2

Summary:
A dimeric enzyme with a 62 kDa polypeptide was purified from the fruit of Malus domestica (apple). This enzyme was demonstrated to have NAD-dependent sorbitol dehydrogenase activity, which reversibly catalyzes the oxidation of D-sorbitol and the reduction of D-fructose [Negm79, Yamaguchi94a]. The specific activity of the enzyme was calculated at 1.11 μmol D-sorbitol.oxidized min-1.mg-1 protein. The enzyme had different pH optima for the oxidation of sorbitol (pH 9.6) and the reduction of fructose (pH 6.0).

The enzyme is not specific to D-sorbitol and was also shown to catalyze the oxidation of xylitol and L-threitol at 84% and 82% of its activity with D-sorbitol [Negm79]. D-mannitol and ribitol were also oxidized but at a relatively low rate compared to the other substrates.

The enzyme has been purified a second time, and was subjected to digestion with trypsin [Yamada98]. Partial amino acid sequences obtained from the fragments were not similar to mammalian liver enzymes. However, a second enzyme, with a subunit size of 42 kDa, has also been purified from apple (see D-sorbitol dehydrogenase) that did resemble the mammalian liver enzymes [Yamada98].

Molecular Weight of Polypeptide: 62 kD (experimental) [Yamaguchi94a ]

Molecular Weight of Multimer: 120 kD (experimental) [Yamaguchi94a]

Gene-Reaction Schematic: ?

Credits:
Revised 03-Nov-2010 by Caspi R , SRI International


Enzymatic reaction of: L-iditol 2-dehydrogenase (D-sorbitol dehydrogenase)

EC Number: 1.1.1.14

L-iditol + NAD+ <=> keto-L-sorbose + NADH + H+

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

Reversibility of this reaction is unspecified.


Enzymatic reaction of: D-xylitol dehydrogenase (D-sorbitol dehydrogenase)

EC Number: 1.1.1.9

xylitol + NAD+ <=> D-xylulose + NADH + H+

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

This reaction is reversible.


Enzymatic reaction of: D-sorbitol dehydrogenase

EC Number: 1.1.1.14

D-sorbitol + NAD+ <=> keto-D-fructose + NADH + H+

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction of enzyme catalysis.

This reaction is reversible.

Alternative Substrates for D-sorbitol: L-threitol [Yamaguchi94a ] , xylitol [Yamaguchi94a ]

In Pathways: D-sorbitol degradation I

Inhibitors (Other): Zn2+ [Yamaguchi94a] , Mg2+ [Yamaguchi94a] , Ca2+ [Yamaguchi94a]

Kinetic Parameters:

Substrate
Km (μM)
Citations
keto-D-fructose
215000.0
[Yamaguchi94a]
D-sorbitol
40300.0
[Yamaguchi94a]


References

Negm79: Negm FB, Loescher WH (1979). "Detection and characterization of sorbitol dehydrogenase from apple callus tissue." Plant Physiol 64(1);69-73. PMID: 16660917

Yamada98: Yamada K, Oura Y, Mori H, Yamaki S (1998). "Cloning of NAD-dependent sorbitol dehydrogenase from apple fruit and gene expression." Plant Cell Physiol 39(12);1375-9. PMID: 10050321

Yamaguchi94a: Yamaguchi H., Kanayama Y., Yamaki S. (1994). "Purification and properties of NAD-dependent sorbitol dehydrogenase from apple fruit." Plant Cell Physiol. 35(6):887-892.


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 Dec 21, 2014, biocyc13.