Hirotani M, Kuroda R, Suzuki H, Yoshikawa T
School of Pharmaceutical Sciences, Kitasato University, Tokyo, Japan.
Planta. 2000 May;210(6):1006-13. doi: 10.1007/PL00008158.
A cDNA encoding UDP-glucose: baicalein 7-O-glucosyltransferase (UBGT) was isolated from a cDNA library from hairy root cultures of Scutellaria baicalensis Georgi probed with a partial-length cDNA clone of a UDP-glucose: flavonoid 3-O-glucosyltransferase (UFGT) from grape (Vitis vinifera L.). The heterologous probe contained a glucosyltransferase consensus amino acid sequence which was also present in the Scutellaria cDNA clones. The complete nucleotide sequence of the 1688-bp cDNA insert was determined and the deduced amino acid sequences are presented. The nucleotide sequence analysis of UBGT revealed an open reading frame encoding a polypeptide of 476 amino acids with a calculated molecular mass of 53,094 Da. The reaction product for baicalein and UDP-glucose catalyzed by recombinant UBGT in Escherichia coli was identified as authentic baicalein 7-O-glucoside using high-performance liquid chromatography and proton nuclear magnetic resonance spectroscopy. The enzyme activities of recombinant UBGT expressed in E. coli were also detected towards flavonoids such as baicalein, wogonin, apigenin, scutellarein, 7,4'-dihydroxyflavone and kaempferol, and phenolic compounds. The accumulation of UBGT mRNA in hairy roots was in response to wounding or salicylic acid treatments.
从黄芩发根培养物的cDNA文库中分离出一个编码UDP - 葡萄糖：黄芩苷7 - O - 葡萄糖基转移酶（UBGT）的cDNA，该文库用来自葡萄（Vitis vinifera L.）的UDP - 葡萄糖：类黄酮3 - O - 葡萄糖基转移酶（UFGT）的部分长度cDNA克隆进行探测。该异源探针包含一个葡萄糖基转移酶共有氨基酸序列，该序列也存在于黄芩cDNA克隆中。测定了1688 bp cDNA插入片段的完整核苷酸序列，并给出了推导的氨基酸序列。UBGT的核苷酸序列分析显示一个开放阅读框，编码一个由476个氨基酸组成的多肽，计算分子量为53,094 Da。使用高效液相色谱和质子核磁共振光谱法，鉴定出重组UBGT在大肠杆菌中催化黄芩苷和UDP - 葡萄糖的反应产物为 authentic黄芩苷7 - O - 葡萄糖苷。还检测了在大肠杆菌中表达的重组UBGT对黄酮类化合物如黄芩苷、汉黄芩素、芹菜素、野黄芩素、7,4'-二羟基黄酮和山奈酚以及酚类化合物的酶活性。UBGT mRNA在发根中的积累是对创伤或水杨酸处理的响应。
