Substrate profiling of cyclohexylamine oxidase and its mutants reveals new biocatalytic potential in deracemization of racemic amines
A cyclohexylamine oxidase (CHAO) of bacterial origin was previously shown to be a potentially useful catalyst in the deracemization of racemic primary amines.To further explore the properties and application of this enzyme, five single-amino acid substitution mutants (L199A, M226A, Y321A, Y321F, and L353M) were created based on superimposition of the tertiary structure of CHAO and the monoamine oxidase (MAO) B homolog.The substrate specificity of the purified wild-type and five mutant enzymes were examined towards 38 structurally diverse amines.All the enzymes exhibited better activity for primary amines than secondary and tertiary amines and in general exhibited high stereoselectivity.Among the mutant enzymes, M226A displayed an enhanced activity (5-400 %) towards most substrates, and L353M showed 7-445 % higher activity towards primary aliphatic amines with cycloalkane or aromatic moieties.Kinetic parameters revealed that both Y32l mutants showed higher catalytic efficiency towards cyclooctanamine, whereas the wild-type CHAO (wt CHAO) was most efficient towards cyclohexylamine.The wt CHAO or variant L353M in combination with a borane-ammonia complex as reducing agent was applied to the deracemization of 1-aminotetraline to give the ?-enantiomer, a precursor of an antidepressant drug Norsertrali he, in good yield (73-76 %), demonstrating their application potential in chiral amine synthesis.
Biocatalysis Monoamine oxidase Site mutagenesis Chiral amines Deracemization Norsertraline
Guangyue Li Jie Ren Hiroaki Iwaki Dalong Zhang Yoshie Hasegawa Qiaqing Wu Jinhui Feng Peter C.K.Lau Dunming Zhu
National Engineering Laboratory for Industrial Enzymes,Tianjin Institute of Industrial Biotechnology Department of Life Science & Biotechnology and ORDIST,Kansai University, Suita, Osaka 564-8680, Japa National Research Council Canada, 6100 Royalmount Avenue,Montreal, QC H4P 2R2, Canada;Departments of
国内会议
苏州
英文
410-420
2014-10-26（万方平台首次上网日期，不代表论文的发表时间）