Complete Conversion of D,L-5-Monosubstituted Hydantoins with a Low Velocity of Chemical Racemization into D-Amino Acids Using Whole

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• 作者：Sergio Martinez-Rodriguez ; Francisco Javier Las Heras-Vazquez ; Josefa Mar&iacute ; a Clemente-Jimenez ; Lydia Mingorance-Cazorla ; and Felipe Rodriguez-Vico
• 刊名：Biotechnology Progress
• 出版年：2002
• 出版时间：December 2002
• 年：2002
• 卷：18
• 期：6
• 页码：1201 - 1206
• 全文大小：148K
• 年卷期：v.18,no.6(December 2002)
• ISSN：1520-6033

文摘

A reaction system was developed for the production of D-amino acids from D,L-5-monosubstituted hydantoins with a very slow rate of spontaneous racemization. Forthis purpose the D-hydantoinase and D-carbamoylase from Agrobacterium radiobacterNRRL B11291 were cloned in separate plasmids and expressed in Escherichia coli.The third enzyme, hydantoin racemase, was cloned from Agrobacterium tumefaciensC58. The hydantoin racemase amino acid sequence was significantly similar to thosepreviously described. A reaction system consisting of recombinant Escherichia coliwhole cell biocatalysts containing separately expressed D-hydantoinase, D-carbamoylase, and hydantoin recemase showed high substrate specificity and was effective towardboth aliphatic and aromatic D,L-5-monosubstituted hydantoins. After optimizingreaction conditions (pH 8 and 50 C), 100% conversion of D,L-5-(2-methylthioethyl)-hydantoin (15 mM) into D-methionine was obtained in 30 min.