A putative aromatic amino acid ammonia-lyase gene (named Pl-pal) was discovered in Photorhabdus luminescens DSM 3368. BLAST and phylogenetic analyses predicted that this enzyme is a histidine ammonia-lyase, whereas sequence alignment suggested that it is more likely a phenylalanine ammonia-lyase (PAL). This gene was amplified from P. luminescens and expressed in Escherichia coli BL21(DE3). The function of Pl-PAL (58 kDa) was characterized by in vitro enzymatic reactions with l-phenylalanine (l-Phe), l-tyrosine (l-Tyr), l-histidine (l-His), and l-tryptophan (l-Trp). Pl-PAL can convert l-Phe and l-Tyr to trans-cinnamic acid and p-coumaric acid, respectively, but had no function on l-His and l-Trp. The optimum temperature and pH were determined to be 40 °C and 11.0, respectively. Under the optimal conditions, Pl-PAL had a k_cat/K_m value of 0.52 s⁻¹ mM⁻¹ with l-Phe as the substrate, while only 0.013 s⁻¹ mM⁻¹ for l-Tyr. Therefore, the primary function of Pl-PAL was determined to be PAL. The Pl-pal-harboring E. coli strain was used as a whole-cell biocatalyst to produce trans-cinnamic acid from l-Phe. The overall molar conversion rate and productivity were 65.98% and 228.10 mg L⁻¹ h⁻¹, respectively, after the cells were repeatedly utilized 7 times. This work thus provides a promising strain for industrial production of trans-cinnamic acid.

在Photorhabdus luminescens DSM 3368中发现了一个假定的芳香族氨基酸氨裂解酶基因（名为Pl-pal）。BLAST和系统发育分析预测该酶是一种组氨酸氨裂解酶，而序列比对表明它更可能是苯丙氨酸氨-裂解酶（PAL）。该基因从发光假单胞菌扩增并在大肠杆菌BL21（DE3）中表达。P1- PAL（58 kDa）的功能通过与1-苯丙氨酸（1- Phe），1-酪氨酸（1 - Tyr ），1-组氨酸（1 - His ）和l-色氨酸（l -Trp）。P1- PAL可以将1- Phe和1- Tyr分别转化为反式肉桂酸和对-香豆酸，但是对1- His和1- Trp没有作用。最佳温度和pH分别确定为40°C和11.0。在最佳条件下，PL -PAL有ķ_猫/ ķ_米0.52价值^-1毫米^-1与升-Phe作为底物，而只有0.013小号^-1毫米^-1为升蒂尔 因此，将P1 -PAL的主要功能确定为PAL。的PL-PAL -harboring大肠杆菌菌株被用作全细胞生物催化剂，以产生反式从-肉桂酸升-Phe。重复使用细胞7次后，总摩尔转化率和生产率分别为65.98％和228.10 mg L ^-1 h ^-1。因此，这项工作为反式肉桂酸的工业生产提供了有希望的菌株。