KEGG   ENZYME: 5.1.99.5Help
Entry
EC 5.1.99.5                 Enzyme                                 

Name
hydantoin racemase;
5'-monosubstituted-hydantoin racemase;
HyuA;
HyuE
Class
Isomerases;
Racemases and epimerases;
Acting on other compounds
BRITE hierarchy
Sysname
D-5-monosubstituted-hydantoin racemase
Reaction(IUBMB)
D-5-monosubstituted hydantoin = L-5-monosubstituted hydantoin [RN:R09704]
Reaction(KEGG)
Substrate
D-5-monosubstituted hydantoin [CPD:C19824]
Product
L-5-monosubstituted hydantoin [CPD:C19825]
Comment
This enzyme, along with N-carbamoylase (EC 3.5.1.77 and EC 3.5.1.87) and hydantoinase, forms part of the reaction cascade known as the "hydantoinase process", which allows the total conversion of D,L-5-monosubstituted hydantoins into optically pure D- or L-amino acids [7]. The enzyme from Pseudomonas sp. (HyuE) has a preference for hydantoins with aliphatic substituents, e.g. D- and L-5-(2-methylthioethyl)hydantoin, whereas that from Arthrobacter aurescens shows highest activity with arylalkyl substituents, especially 5-benzylhydantoin, at the 5-position [2]. In the enzyme from Sinorhizobium meliloti, Cys76 is responsible for recognition and proton retrieval of D-isomers, while Cys181 is responsible for L-isomer recognition and racemization [6].
History
EC 5.1.99.5 created 2008
Reference
1  [PMID:1459947]
  Authors
Watabe K, Ishikawa T, Mukohara Y, Nakamura H
  Title
Purification and characterization of the hydantoin racemase of Pseudomonas sp. strain NS671 expressed in Escherichia coli.
  Journal
J. Bacteriol. 174 (1992) 7989-95.
Reference
2  [PMID:10949312]
  Authors
Wiese A, Pietzsch M, Syldatk C, Mattes R, Altenbuchner J
  Title
Hydantoin racemase from Arthrobacter aurescens DSM 3747: heterologous expression, purification and characterization.
  Journal
J. Biotechnol. 80 (2000) 217-30.
Reference
3  [PMID:14711700]
  Authors
Martinez-Rodriguez S, Las Heras-Vazquez FJ, Mingorance-Cazorla L, Clemente-Jimenez JM, Rodriguez-Vico F
  Title
Molecular cloning, purification, and biochemical characterization of hydantoin racemase from the legume symbiont Sinorhizobium meliloti CECT 4114.
  Journal
Appl. Environ. Microbiol. 70 (2004) 625-30.
Reference
4  [PMID:15016445]
  Authors
Martinez-Rodriguez S, Las Heras-Vazquez FJ, Clemente-Jimenez JM, Rodriguez-Vico F
  Title
Biochemical characterization of a novel hydantoin racemase from Agrobacterium tumefaciens C58.
  Journal
Biochimie. 86 (2004) 77-81.
Reference
5  [PMID:15784981]
  Authors
Suzuki S, Onishi N, Yokozeki K
  Title
Purification and characterization of hydantoin racemase from Microbacterium liquefaciens AJ 3912.
  Journal
Biosci. Biotechnol. Biochem. 69 (2005) 530-6.
Reference
6  [PMID:17132860]
  Authors
Martinez-Rodriguez S, Andujar-Sanchez M, Neira JL, Clemente-Jimenez JM, Jara-Perez V, Rodriguez-Vico F, Las Heras-Vazquez FJ
  Title
Site-directed mutagenesis indicates an important role of cysteines 76 and 181 in the catalysis of hydantoin racemase from Sinorhizobium meliloti.
  Journal
Protein. Sci. 15 (2006) 2729-38.
Reference
7  [PMID:11849938]
  Authors
Altenbuchner J, Siemann-Herzberg M, Syldatk C
  Title
Hydantoinases and related enzymes as biocatalysts for the synthesis of unnatural chiral amino acids.
  Journal
Curr. Opin. Biotechnol. 12 (2001) 559-63.
Other DBs
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IUBMB Enzyme Nomenclature: 
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BRENDA, the Enzyme Database: 

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