ID 3.5.2.17 DE hydroxyisourate hydrolase. AN 5-hydroxyisourate hydrolase. AN HIUHase. CA 5-hydroxyisourate + H2O = 5-hydroxy-2-oxo-4-ureido-2,5-dihydro- CA 1H-imidazole-5-carboxylate + H(+). CC -!- The reaction is the first stage in the conversion of CC 5-hydroxyisourate into (S)-allantoin. CC -!- This reaction will also occur spontaneously, but more slowly. DR Q21882, HIUH1_CAEEL; Q92VB9, HIUH1_RHIME; O44578, HIUH2_CAEEL; DR Q92UG5, HIUH2_RHIME; O32142, HIUH_BACSU ; Q8YFU1, HIUH_BRUME ; DR Q8G228, HIUH_BRUSU ; Q9A545, HIUH_CAUVC ; Q06S87, HIUH_DANRE ; DR Q9RV69, HIUH_DEIRA ; Q8XB75, HIUH_ECO57 ; P76341, HIUH_ECOLI ; DR Q9KET9, HIUH_HALH5 ; Q9CRB3, HIUH_MOUSE ; Q9I3J5, HIUH_PSEAE ; DR Q8XXJ7, HIUH_RALN1 ; Q98CI7, HIUH_RHILO ; Q4VYA5, HIUH_SALDU ; DR Q8Z7Q6, HIUH_SALTI ; Q8ZQ52, HIUH_SALTY ; O74492, HIUH_SCHPO ; DR Q8S3J3, HIUH_SOYBN ; Q9LVM5, TTHL_ARATH ; //