College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310030, Zhejiang, China.
TCM and Ethnomedicine Innovation and Development Laboratory, School of Pharmacy, Hunan University of Chinese Medicine, Changsha, 410208, Hunan, China.
Bioprocess Biosyst Eng. 2020 Jul;43(7):1287-1298. doi: 10.1007/s00449-020-02325-5. Epub 2020 Mar 20.
p-Coumaric acid (p-CA) is a bioactive natural product and an important industrial material for pharmaceuticals and nutraceuticals. It can be synthesized from deamination of L-tyrosine by tyrosine ammonia lyase (TAL). In this work, we discovered two aromatic amino acid lyase genes, Sas-tal and Sts-tal, from Saccharothrix sp. NRRL B-16348 and Streptomyces sp. NRRL F-4489, respectively, and expressed them in Escherichia coli BL21(DE3). The two enzymes were functionally characterized as TAL. The optimum reaction temperature for Sas-TAL and Sts-TAL is 55 °C and 50 °C, respectively; while, the optimum pH for both TALs is 11. Sas-TAL had a k/K value of 6.2 μM min, while Sts-TAL had a much higher efficiency with a k/K value of 78.3 μM min. Both Sts-TAL and Sas-TAL can also take L-phenylalanine as the substrate to yield trans-cinnamic acid, and Sas-TAL showed much higher phenylalanine ammonia lyase activity than Sts-TAL. Using E. coli/Sts-TAL as a whole-cell biocatalyst, the productivity of p-CA reached 2.88 ± 0.12 g (L h), which represents the highest efficiency for microbial production of p-CA. Therefore, this work not only reports the identification of two new TALs from actinomycetes, but also provides an efficient way to produce the industrially valuable material p-CA.
对羟基肉桂酸（p-CA）是一种生物活性天然产物，也是药物和营养保健品的重要工业原料。它可以通过酪氨酸脱氨酶（TAL）对 L-酪氨酸进行脱氨合成。在这项工作中，我们从 Saccharothrix sp. NRRL B-16348 和 Streptomyces sp. NRRL F-4489 中分别发现了两种芳香族氨基酸裂解酶基因 Sas-tal 和 Sts-tal，并在大肠杆菌 BL21(DE3)中进行了表达。这两种酶的功能被鉴定为 TAL。Sas-TAL 和 Sts-TAL 的最适反应温度分别为 55°C 和 50°C；而两种 TAL 的最适 pH 值均为 11。Sas-TAL 的 k/K 值为 6.2 μM·min，而 Sts-TAL 的效率更高，k/K 值为 78.3 μM·min。Sts-TAL 和 Sas-TAL 均可作为 L-苯丙氨酸的底物生成反式肉桂酸，且 Sas-TAL 的苯丙氨酸氨裂解酶活性明显高于 Sts-TAL。使用大肠杆菌/Sts-TAL 作为全细胞生物催化剂，p-CA 的产量达到 2.88±0.12 g·(L·h)，这代表了微生物生产 p-CA 的最高效率。因此，这项工作不仅报道了两种来自放线菌的新型 TAL 的鉴定，还提供了一种高效生产工业价值材料 p-CA 的方法。
