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Substrate profiling of cyclohexylamine oxidase and its mutants reveals new biocatalytic potential in deracemization of racemic amines.
Li, Guangyue; Ren, Jie; Iwaki, Hiroaki; Zhang, Dalong; Hasegawa, Yoshie; Wu, Qiaqing; Feng, Jinhui; Lau, Peter C K; Zhu, Dunming.
Affiliation
  • Li G; National Engineering Laboratory for Industrial Enzymes, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 Xi Qi Dao, Tianjin Airport Economic Area, Tianjin, 300308, People's Republic of China.
Appl Microbiol Biotechnol ; 98(4): 1681-9, 2014 Feb.
Article in En | MEDLINE | ID: mdl-23793344
ABSTRACT
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 Y321 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 (R)-enantiomer, a precursor of an antidepressant drug Norsertraline, in good yield (73-76%), demonstrating their application potential in chiral amine synthesis.
Subject(s)

Full text: 1 Collection: 01-internacional Database: MEDLINE Main subject: Oxidoreductases Acting on CH-NH Group Donors / Amines Language: En Journal: Appl Microbiol Biotechnol Year: 2014 Type: Article

Full text: 1 Collection: 01-internacional Database: MEDLINE Main subject: Oxidoreductases Acting on CH-NH Group Donors / Amines Language: En Journal: Appl Microbiol Biotechnol Year: 2014 Type: Article