Departamento de Microbiología, Instituto de Fermentaciones Industriales, Consejo Superior de Investigaciones Científicas, Juan de Cierva 3, 28006 Madrid, Spain.
J Ind Microbiol Biotechnol. 2010 Jun;37(6):617-24. doi: 10.1007/s10295-010-0709-6. Epub 2010 Mar 24.
Phenolic acid decarboxylase (PAD) catalyzes the synthesis of vinyl phenols from hydroxycinnamic acids. The gene encoding PAD from Lactobacillus brevis was cloned and expressed as a fusion protein in Escherichia coli. The recombinant PAD enzyme is a heat-labile enzyme that functions optimally at 22 degrees C and pH 6.0. The purified enzyme did not show thermostability at temperatures above 22 degrees C. L. brevis PAD is able to decarboxylate exclusively the hydroxycinnamic acids, such as p-coumaric, caffeic, and ferulic acids, with K (m) values of 0.98, 0.96, and 0.78 mM, respectively. The substrate specificity exhibited by L. brevis PAD is similar to the PAD isolated from Bacillus subtilis and B. pumilus, but different from that of L. plantarum and Pediococcus pentosaceus. As the C-terminal region may be involved in determining PAD substrate specificity and catalytic capacity, amino acid differences among these proteins could explain the differences observed. The substrate specificity shown by L. brevis PAD shows promise for the synthesis of high-added value products from plant wastes.
酚酸脱羧酶（PAD）催化羟基肉桂酸合成乙烯基酚。从短乳杆菌中克隆并在大肠杆菌中表达了编码 PAD 的基因，作为融合蛋白。重组 PAD 酶是一种热不稳定酶，在 22°C 和 pH6.0 下最佳发挥作用。纯化后的酶在 22°C 以上的温度下没有表现出热稳定性。短乳杆菌 PAD 能够专一地脱羧羟基肉桂酸，如对香豆酸、咖啡酸和阿魏酸，其 K（m）值分别为 0.98、0.96 和 0.78mM。短乳杆菌 PAD 表现出的底物特异性类似于从枯草芽孢杆菌和地衣芽孢杆菌中分离出的 PAD，但与植物乳杆菌和戊糖片球菌的 PAD 不同。由于 C 末端区域可能参与决定 PAD 的底物特异性和催化能力，这些蛋白质中的氨基酸差异可以解释观察到的差异。短乳杆菌 PAD 表现出的底物特异性有望从植物废料中合成高附加值产品。
