Species: Cavia porcellus
The enzyme catalyzing the oxidation of 4-imidazolone-5-propanoate to hydantoin-5-propanoate 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 22.214.171.124 ) 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].
Enzymatic reaction of: 4-imidazolone-5-propionate oxidase
EC Number: 1.17.3.-4-imidazolone-5-propanoate + oxygen + H2O → hydantoin-5-propanoate + hydrogen peroxide
The direction shown, i.e. which substrates are on the left and right sides, is in accordance with the direction in which it was curated.
The reaction is physiologically favored in the direction shown.
In Pathways: L-histidine degradation VIhydrogen cyanide [Hassall68] Inhibitors (Unknown Mechanism): atabrine [Hassall68]Kinetic Parameters:
pH(opt): 5.8 [Hassall68]
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
©2016 SRI International, 333 Ravenswood Avenue, Menlo Park, CA 94025-3493