Laboratory of Carbohydrate Chemistry and Enzymology, 4252 Molecular Biology Bldg., Iowa State University, Ames, IA 50011, USA.
Carbohydr Res. 2009 Nov 23;344(17):2349-56. doi: 10.1016/j.carres.2009.06.041. Epub 2009 Jul 9.
Dopamine-HCl and L-DOPA-alpha-glycosides were prepared by reaction with cyclomaltohexaose, catalyzed by Bacillus macerans cyclomaltodextrin glucanyltransferase. The reaction gave maltodextrins attached to dopamine and L-DOPA; the maltodextrins were trimmed by reactions with glucoamylase and beta-amylase to produce alpha-glucosyl- and alpha-maltosyl-glycosides, respectively. The glucoamylase- or beta-amylase-treated dopamine- and L-DOPA-alpha-glycosides were fractionated and purified by BioGel P-2 gel-filtration column chromatography and preparative descending paper chromatography. Analysis by MALDI-TOF mass spectrometry and one- and two-dimensional NMR showed that the purified glycosides of dopamine and L-DOPA were glycosylated at the hydroxyl groups of positions 3 and 4 of the catechol ring. The major product was found to be 4-O-alpha-glycopyranosyl L-DOPA, and it was shown to be more resistant to oxidative tolerance experiments, involving hydrogen peroxide and ferrous ion, than L-DOPA. L-DOPA-alpha-glycosides are possibly more effective substitutes for L-DOPA in treating Parkinson's disease in that they are more resistant to oxidation and methylation, which renders L-DOPA ineffective and deleterious.
盐酸多巴胺和 L-多巴-α-糖苷通过与环麦芽六糖反应，在巨大芽孢杆菌环麦芽寡糖糖基转移酶的催化下制备得到。该反应使多巴胺和 L-多巴与麦芽低聚糖相连；通过与糖化酶和β-淀粉酶反应，将麦芽低聚糖修剪，分别产生α-葡萄糖基-和α-麦芽糖基-糖苷。用糖化酶或β-淀粉酶处理后的多巴胺和 L-多巴-α-糖苷通过 BioGel P-2 凝胶过滤柱层析和制备性下降纸层析进行分离和纯化。通过 MALDI-TOF 质谱和一维及二维 NMR 分析表明，多巴胺和 L-多巴的糖苷化产物在儿茶酚环的 3 位和 4 位的羟基上发生了糖苷化。主要产物被鉴定为 4-O-α-吡喃葡萄糖基-L-多巴，并且与 L-多巴相比，它对涉及过氧化氢和亚铁离子的氧化耐受性实验更具抗性。L-多巴-α-糖苷可能是治疗帕金森病的更有效的 L-多巴替代品，因为它们对氧化和甲基化更具抗性，这会使 L-多巴失去疗效并产生有害作用。
