(3−5) Among them, ω-transaminases (ω-TAs), which catalyze the transfer of ketone and amino groups, have received extensive attention. These methods mainly involve enzymes such as amine oxidases, ammonia lyases, amine dehydrogenases, and transaminases. (2) In order to overcome the drawbacks of low enantioselectivity, need for noble-metal catalysts, harsh reaction conditions, and environmental concerns in asymmetric synthesis, several biochemical methods using efficient biocatalysts have been developed and managed to replace chemical methods. As far as chemical methods are concerned, chiral amines are usually produced by the asymmetric catalysis of prochiral molecules, such as hydrogenation of imine or enamine, alkylation of imine, amino hydroxylation, and reductive amination. (1) The production of chiral amines includes chemical and biochemical methods. The Q192G mutant was then used to convert two cyclic ketones, N-Boc-3-pyrrolidinone and N-Boc-3-piperidone, and both the conversions were obviously improved compared to that of the parental CbTA.Ĭhiral amines are very important intermediates, which have a wide range of applications in medicine and fine chemical industries. CbTA evolved by site-specific mutagenesis and found that the Q192G mutant increased the activity to ( R)-MBA by around 9.8-fold. The homology model of CbTA was built by Discovery Studio, and docking was performed to describe the relative activity toward some substrates. More importantly, CbTA also exhibited good affinity toward some cyclic substrates. The substrate acceptability test showed that CbTA has significant reactivity to aromatic amino donors and amino receptors. The results showed that the recombinant CbTA has a specific activity of 1.19 U/mg for ( R)-α-methylbenzylamine at pH 8.5 and 45 ☌. The gene sequence of CbTA was inserted into pRSF-Duet1 and functionally expressed in Escherichia coli BL21(DE3). bacterium ( CbTA) shows 38% sequence identity to that of ATA117 Arrmut11. KNK168 and amine transaminase from Aspergillus terreus NIH2624) as templates in a BLASTP search and motif sequence alignment. In the present study, we have identified an ω-transaminase (ω-TA) from Chloroflexi bacterium from the genome database by using two ω-TA sequences (ATA117 Arrmut11 from Arthrobacter sp.
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