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ENZYME entry: EC

Accepted Name
Hydantoin racemase.
Alternative Name(s)
5'-monosubstituted-hydantoin racemase.
Reaction catalysed
D-5-monosubstituted hydantoin <=> L-5-monosubstituted hydantoin
  • This enzyme, along with EC, EC and EC, 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.
  • 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.
  • In the enzyme from Sinorhizobium meliloti, Cys-76 is responsible for recognition and proton retrieval of D-isomers, while Cys-181 is responsible for L-isomer recognition and racemization.
PRIAM enzyme-specific profiles5.1.99.5
KEGG Ligand Database for Enzyme Nomenclature5.1.99.5
IUBMB Enzyme Nomenclature5.1.99.5
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