The chiral amine (R)-2-(1-aminoethyl)-4-fluorophenol has attracted increasing attentions in recent years in the field of pharmaceuticals because of its important use as a building block in the synthesis of novel anti-tumor drugs targeting tropomyosin receptor kinases. In the present study, a ω-transaminase (ωTA) library consisting of 21 (R)-enantioselective enzymes was constructed and screened for the asymmetric biosynthesis of (R)-2-(1-aminoethyl)-4-fluorophenol from its prochiral ketone. Using (R)-α-methylbenzylamine, D-alanine, or isopropylamine as amino donor, 18 ωTAs were identified with target activity and the enzyme AbTA, which was originally identified from Arthrobacter sp. KNK168, was found to be a potent candidate. The E. coli whole cells expressing AbTA could be used as catalysts. The optimal temperature and pH for the activity were 35-40°C and pH8.0, respectively. Simple alcohols (such as ethanol, isopropanol, and methanol) and dimethyl sulfoxide were shown to be good cosolvents. High activities were detected when using ethanol and dimethyl sulfoxide at the concentrations of 5-20%. In the scaled-up reaction of 1-liter containing 13 mM ketone substrate, about 50% conversion was achieved in 24 h. 6.4 mM (R)-2-(1-aminoethyl)-4-fluorophenol was generated. After a simple and efficient process of product isolation and purification (with 98.8% recovery), 0.986 g yellowish powder of the product (R)-2-(1-aminoethyl)-4-fluorophenol with high (R)-enantiopurity (up to 100% enantiomeric excess) was obtained. This study established an overall process for the biosynthesis of the high value pharmaceutical chiral amine (R)-2-(1-aminoethyl)-4-fluorophenol by ωTA. Its applicable potential was exemplified by gram-scale production.

手性胺( R )-2-(1-氨基乙基)-4-氟苯酚近年来在医药领域引起了越来越多的关注，因为它在合成针对原肌球蛋白的新型抗肿瘤药物中具有重要的用途。受体激酶。在本研究中，构建了由21个( R )-对映选择性酶组成的ω-转氨酶(ωTA)文库，并筛选了从其前手性酮不对称生物合成( R )-2-(1-氨基乙基)-4-氟苯酚的方法。 。使用 ( R )-α-甲基苄胺、D-丙氨酸或异丙胺作为氨基供体，鉴定出具有目标活性的 18 个 ωTA 以及最初从节杆菌属中鉴定出的酶 AbTA。 KNK168，被发现是一个有效的候选者。表达 AbTA 的大肠杆菌全细胞可用作催化剂。该活性的最适温度和pH分别为35-40℃和pH8.0。简单的醇（如乙醇、异丙醇和甲醇）和二甲亚砜被证明是良好的共溶剂。当使用浓度为 5-20% 的乙醇和二甲亚砜时，检测到高活性。在含有 13 mM 酮底物的 1 升放大反应中，24 小时内实现了约 50% 的转化。生成 6.4 mM ( R )-2-(1-氨基乙基)-4-氟苯酚。经过简单高效的产物分离纯化过程（回收率98.8%），得到0.986g淡黄色粉末状产物（ R ）-2-（1-氨基乙基）-4-氟苯酚，具有高（ R ）-对映体纯度（高达获得100%对映体过量）。 本研究建立了利用ωTA生物合成高价值药用手性胺( R )-2-(1-氨基乙基)-4-氟苯酚的整体工艺。克级生产证明了其应用潜力。