Huang Yawen, Jiang Xiaolong, Chen Wujiu, Zhang Guimin, Wang Qinhong
State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei University, Wuhan 430062, Hubei, China.
Tianjin Institute of Industrial Biotechnology, Chinese Academy of Science, Tianjin 300308, China.
Sheng Wu Gong Cheng Xue Bao. 2022 Dec 25;38(12):4553-4566. doi: 10.13345/j.cjb.220182.
-coumaric acid is one of the aromatic compounds that are widely used in food, cosmetics and medicine due to its properties of antibacterium, antioxidation and cardiovascular disease prevention. Tyrosine ammonia-lyase (TAL) catalyzes the deamination of tyrosine to -coumaric acid. However, the lack of highly active and specific tyrosine ammonia lyase limits cost-effective microbial production of -coumaric acid. In order to improve biosynthesis efficiency of -coumaric acid, two tyrosine ammonia-lyases, namely Fc-TAL2 derived from and Fs-TAL derived from , were selected and characterized. The optimum temperature (55 ℃) and pH (9.5) for Fs-TAL and Fc-TAL2 are the same. Under optimal conditions, the specific enzyme activity of Fs-TAL and Fc-TAL2 were 82.47 U/mg and 13.27 U/mg, respectively. Structural simulation and alignment analysis showed that the orientation of the phenolic hydroxyl group of the conserved Y50 residue on the inner lid loop and its distance to the substrate were the main reasons accounting for the higher activity of Fs-TAL than that of Fc-TAL2. The higher activity and specificity of Fs-TAL were further confirmed via whole-cell catalysis using recombinant , which could convert 10 g/L tyrosine into 6.2 g/L -coumaric acid with a yield of 67.9%. This study provides alternative tyrosine ammonia-lyases and may facilitate the microbial production of -coumaric acid and its derivatives.
对香豆酸是一种芳香族化合物，因其具有抗菌、抗氧化和预防心血管疾病的特性而被广泛应用于食品、化妆品和医药领域。酪氨酸解氨酶（TAL）催化酪氨酸脱氨生成对香豆酸。然而，缺乏高活性和特异性的酪氨酸解氨酶限制了对香豆酸的经济高效微生物生产。为了提高对香豆酸的生物合成效率，选择并表征了两种酪氨酸解氨酶，即来源于[具体来源1]的Fc-TAL2和来源于[具体来源2]的Fs-TAL。Fs-TAL和Fc-TAL2的最适温度（55℃）和pH（9.5）相同。在最佳条件下，Fs-TAL和Fc-TAL2的比酶活分别为82.47 U/mg和13.27 U/mg。结构模拟和比对分析表明，内盖环上保守的Y50残基的酚羟基方向及其与底物的距离是Fs-TAL活性高于Fc-TAL2的主要原因。通过使用重组[具体菌株]进行全细胞催化进一步证实了Fs-TAL具有更高的活性和特异性，其可将10 g/L酪氨酸转化为6.2 g/L对香豆酸，产率为67.9%。本研究提供了替代的酪氨酸解氨酶，并可能促进对香豆酸及其衍生物的微生物生产。
