Properties of D-hydantoinase from Agrobacterium tumefaciens and its use for the preparation of N-carbamyl D-amino acids.
Agrobacterium tumefaciens strain 47C expresses an inducible D-hydantoinase that catalyzes the formation of optically pure N-carbamyl D-amino acids from racemic hydantoin precursors. The D-Hydantoinase was shown to be active and stable at elevated temperatures and pH values, thus affording favorable bioreaction conditions that result in the racemization of DL-hydantoins to the utilizable D-isomer. The enzyme demonstrated optimal reaction kinetics at pH 10 and 70 degrees C, was not activated by metal ions, and exhibited a distinctive substrate specificity. A. tumefacins hydantoinase was most active on 5,6-dihydrouracil and DL-5-methylhydantoin with only slight activity on DL-benzylhydantoin. Extracts or whole cells of A. tumefaciens were used as biocatalyst to mediate the stereospecific conversion of DL-phenylhydantoin or DL-5-methylhydantoin to the respective N-carbamyl D-amino acids. In addition, immobilized cell systems were shown to be useful for biocatalyst reuse.
D016960:Agrobacterium tumefaciens / Q000201:enzymology*; D000581:Amidohydrolases / Q000378:metabolism*; D006827:Hydantoins / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008670:Metals / Q000494:pharmacology; D010648:Phenylacetates / Q000378:metabolism*; D013237:Stereoisomerism; D013379:Substrate Specificity; D013696:Temperature; D014498:Uracil / Q000031:analogs & derivatives / Q000378:metabolism; D014508:Urea / Q000031:analogs & derivatives* / Q000378:metabolism
D006827:Hydantoins; D008670:Metals; D010648:Phenylacetates; C007419:dihydrouracil; D014498:Uracil; C047589:5-methylhydantoin; C096868:N-carbamyl(phenyl)glycine; D014508:Urea; D000581:Amidohydrolases; C020047:dihydropyrimidinase