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Simultaneous synthesis of enantiomerically pure ( S )‐amino acids and ( R )‐amines using coupled transaminase reactions
Author(s) -
Cho ByungKwan,
Cho Ho Jung,
Park SungHee,
Yun Hyungdon,
Kim ByungGee
Publication year - 2003
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.10526
Subject(s) - transaminase , chemistry , transamination , decarboxylation , amino acid , yield (engineering) , aspartate transaminase , reaction rate constant , amine gas treating , enantioselective synthesis , stereochemistry , alanine , organic chemistry , medicinal chemistry , catalysis , enzyme , biochemistry , kinetics , materials science , alkaline phosphatase , metallurgy , physics , quantum mechanics
For the simultaneous synthesis of enatiomerically pure ( S )‐amino acids and ( R )‐amines from corresponding α‐keto acids and racemic amines, an α/ω‐transaminase coupled reaction system was designed using favorable reaction equilibrium shift led by ω‐transaminase reaction. Cloned tyr B, asp C and avt A, and ω ta A were co‐expressed in E. coli BL21(DE3) using pET23b(+) and pET24ma, respectively. The coupled reaction produced the ( S )‐amino acids with 73–90% (> 99% ee S ) of conversion yield and resolved the racemic amines with 83–99% ee R for 5 to 10 hours. In designing the coupled reactions in the cell, alanine and pyruvate were efficiently used in the cell as an amine donor for the alanine transaminase and an amino acceptor for the ω‐transaminase, respectively, resulting in an alanine‐pyruvate shuttling system. The common problem of the low equilibrium constant of the α‐transaminase can be efficiently overcome by the coupling with the ω‐transaminase. However, overcoming the product inhibition of ω‐transaminase by the ketone by‐product and increasing the decarboxylation rate of the oxaloacetate produced during the transaminase reaction become barriers to further improving the overall reaction rate and the yield of the coupled reactions. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 81: 783–789, 2003.