β-葡萄糖醛酸苷酶荧光底物试卤灵葡萄糖醛酸苷的高效制备

以猴肝微粒体(CyLM)为酶源, 采用生物制备法实现了荧光底物试卤灵(Resorufin)向试卤灵葡萄糖醛酸苷(Resorufin β-D-glucuronide)的高效转化, 同时借助新型色谱分离材料C18WAX及固相萃取技术实现了Resorufin β-D-glucuronide的高效富集及选择性洗脱, 最终获得纯度大于98%的目标产物. 所得产物结构经LC-MS, ¹H NMR和¹³C NMR等手段进行了表征. 在此基础上, 以该葡萄糖醛酸产物为探针底物建立了β-葡萄糖醛酸苷酶活性检测及抑制剂高通量筛选的方法.

Highly Efficient Preparation of Resorufin-β-D-glucuronide†

Resorufin-β-O-glucuronide(REG) is a substrate of the β-glucuronidase enzyme which exhibited almost no fluorescence, upon addition of β-glucuronidase a high fluorescent compound resorufin will be released. Resorufin, is a fluorescent compound possessing good optical properties. On the basis of the off-on type fluorescent reaction, REG can be served as the good fluorescent substrate of β-glucuronidase. However, commercial available REG is rather expensive due to the difficulty for preparation of REG and the studies on REG are very limited. This study aimed to adopt the mild biosynthesis approach to efficiently prepare REG, based on resorufin can be extensively metabolized to REG by UDP-glucuronosyltransferases(UGTs). REG was prepared using resorufin as the starting material and liver microsomes from cynomolgus monkeys(CyLM) as the enzyme source. Resorufin(RE, 100 μmol/L) was incubated in Tris-HCl(50 mmol/L, pH=7.4, with 1% DMSO) with CyLM(0.5 mg/mL) at 37 ℃ for 4 h. After the optimization of the incubation conditions, the conversion of REG was more than 80%. A unique solid-phase extraction column(SPE) packed with C18WAX was used to enrich and purify the product REG with high yield. The product was then identified by both LC-MS and NMR techniques. Finally, a high throughput screening method for β-glucuronidase inhibitors was well established, based on the accurate kinetic parameters of REG towards β-glucuronidase and the absorption and emission spectrum of REG.