Division of Applied Bioscience, Research Faculty of Agriculture, Hokkaido University, N-9, W-9, Kita-Ku, Sapporo 060-8589, Japan.
Phytochemistry. 2010 Aug;71(11-12):1280-8. doi: 10.1016/j.phytochem.2010.04.025.
Tuberonic acid (TA) and its glucoside (TAG) have been isolated from potato (Solanum tuberosum L.) leaflets and shown to exhibit tuber-inducing properties. These compounds were reported to be biosynthesized from jasmonic acid (JA) by hydroxylation and subsequent glycosylation, and to be contained in various plant species. Here we describe the in vivo hydrolytic activity of TAG in rice. In this study, the TA resulting from TAG was not converted into JA. Tuberonic acid glucoside (TAG)-hydrolyzing beta-glucosidase, designated OsTAGG1, was purified from rice by six purification steps with an approximately 4300-fold purification. The purified enzyme migrated as a single band on native PAGE, but as two bands with molecular masses of 42 and 26 kDa on SDS-PAGE. Results from N-terminal sequencing and peptide mass fingerprinting of both polypeptides suggested that both bands were derived from a single polypeptide, which is a member of the glycosyl hydrolase family 1. In the native enzyme, the K(m) and V(max) values of TAG were 31.7 microM and 0.25 microkatal/mg protein, OsTAGG1 preferentially hydrolyzed TAG and methyl TAG. Here we report that OsTAGG1 is a specific beta-glucosidase hydrolyzing TAG, which releases the physiologically active TA.
块茎酸（TA）及其糖苷（TAG）已从马铃薯（Solanum tuberosum L.）叶片中分离出来，并显示出诱导块茎的特性。据报道，这些化合物是通过茉莉酸（JA）的羟化和随后的糖基化生物合成的，并且存在于各种植物物种中。在这里，我们描述了 TAG 在水稻中的体内水解活性。在这项研究中，TAG 产生的 TA 没有转化为 JA。从水稻中通过六个纯化步骤纯化出 TAG 水解β-葡萄糖苷酶，命名为 OsTAGG1。纯化酶在天然 PAGE 上迁移为单一条带，但在 SDS-PAGE 上迁移为两条带，分子量分别为 42 和 26 kDa。两种多肽的 N 末端测序和肽质量指纹图谱结果表明，这两条带均源自一种单一多肽，该多肽属于糖苷水解酶家族 1。在天然酶中，TAG 的 K(m)和 V(max)值分别为 31.7 μM 和 0.25 微千分每毫克蛋白，OsTAGG1 优先水解 TAG 和甲基 TAG。在这里，我们报告 OsTAGG1 是一种特异性的水解 TAG 的β-葡萄糖苷酶，它释放具有生理活性的 TA。
