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Metabolic Modeling Tutorial
discounted EARLY registration ends Dec 31, 2014
BioCyc websites down
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Metabolic Modeling Tutorial
discounted EARLY registration ends Dec 31, 2014
BioCyc websites down
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for maintenance.
Metabolic Modeling Tutorial
discounted EARLY registration ends Dec 31, 2014
BioCyc websites down
12/28 - 12/31
for maintenance.
Metabolic Modeling Tutorial
discounted EARLY registration ends Dec 31, 2014
BioCyc websites down
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MetaCyc Enzyme: 4-imidazolone-5-propionate oxidase

Species: Cavia porcellus

Summary:
The enzyme catalyzing the oxidation of 4-imidazolone-5-propionate to hydantoin-5-propionate has been partially purified from Cavia porcellus (guinea pig). The enzyme contained FAD, and removal of the FAD cofactor destroyed the enzyme's activity. The addition of FAD to the inactive enzyme did not restore activity. The reaction consumed 0.5 mole of oxygen per mole of product formed [Hassall68].

It was previously shown that this reaction can be be catalyzed by a a xanthine oxidase (EC 1.17.3.2 ) isolated from milk [Hassall63]. However, 4-imidazolone-5-propionate oxidase from Cavia porcellus is clearly a different enzyme, as, unlike a xanthine oxidase, it was not able to oxidize xanthine [Hassall68].

Gene-Reaction Schematic: ?


Enzymatic reaction of: 4-imidazolone-5-propionate oxidase

EC Number: 1.17.3.-

4-imidazolone-5-propionate + oxygen + H2O <=> hydantoin-5-propionate + hydrogen peroxide

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 physiologically favored in the direction shown.

In Pathways: histidine degradation VI

Cofactors or Prosthetic Groups: FAD [Hassall68]

Inhibitors (Other): hydrogen cyanide [Hassall68]

Inhibitors (Unknown Mechanism): atabrine [Hassall68]

Kinetic Parameters:

Substrate
Km (μM)
Citations
4-imidazolone-5-propionate
500.0
[Hassall68]

pH(opt): 5.8 [Hassall68]


References

Hassall63: Hassall, H., Greenberg, D.M. (1963). "The oxidation of 4(5)-imidazolone-5(4)-propionic acid to hydantoin-5-propionic acid by xanthine oxidase." Biochim Biophys Acta 67;507-10. PMID: 13960896

Hassall68: Hassall H, Greenberg DM (1968). "Studies on the enzymic decomposition of urocanic acid. VI. Properties of the enzyme catalyzing the oxidation of 4(5)-imidazolone-5(4)-propionic acid to L-hydantoin-5-propionic acid." Arch Biochem Biophys 125(1);278-85. PMID: 4967723


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, BIOCYC14B.