High yielding one-pot enzyme-catalyzed synthesis of UDP-glucose in gram scales
摘要:
Uridine diphosphoglucose is an important cofactor of glucosylating enzymes. A simple and high yielding one-pot enzymatic synthesis of UDPG on a gram scale from glucose via hexokinase, phosphoglucomutase and UDPG pyrophosphorylase (UGPase) is described. Repetitive addition of substrate was used to avoid inhibition of UGPase. The approach allows recovery of active enzymes and their re-use. The synthesis of UDP-[4-C-13]-glucose on a 0.5 g scale resulted in a final yield of 70% and a purity of > 95% after chromatographic purification. (C) 2001 Elsevier Science Ltd. All rights reserved.
Gas-Phase Intercluster Thiyl-Radical Induced C–H Bond Homolysis Selectively Forms Sugar C2-Radical Cations of Methyl D-Glucopyranoside: Isotopic Labeling Studies and Cleavage Reactions
作者:Sandra Osburn、Gaetano Speciale、Spencer J. Williams、Richard A. J. O’Hair
DOI:10.1007/s13361-017-1667-2
日期:2017.7.1
exchangeable OH and NH protons with deuterons reveals that the sugar radical cation is formed in a process involving abstraction of a hydrogenatom from a C-H bond of the sugar coupled with proton transfer to the sugar, to form [M - H• + D+]. Investigation of this process using individual C-D labeled sugars reveals that the main site of H/D abstraction is the C2 position, since only the C2-deuterium
一组甲基D-吡喃葡萄糖苷的同位素异构体与多级质谱实验结合使用,以确定通过最近开发的“生物启发”方法形成的糖自由基阳离子的自由基位点和裂解反应。在CID(MS2)的第一阶段,糖和S-亚硝基半胱胺[H3NCH2CH2SNO + M] +之间的质子化非共价复合物的碰撞诱导解离(CID)通过键均解释放硫代自由基,得到非共价自由基阳离子,[H3NCH2CH2S•+ M] +。该自由基阳离子复合物的CID(MS3)导致非共价复合物解离,生成糖自由基阳离子。用氘核取代所有可交换的OH和NH质子表明,糖自由基阳离子是在一个过程中形成的,该过程涉及从糖的CH键中夺取氢原子,然后将质子转移到糖中,从而形成[M-H•+ D +]。使用单个CD标记的糖对此过程进行的研究表明,H / D提取的主要位点是C2位置,因为只有C2氘标记的糖会产生占主导地位的[M-D•+ H +]产物离子。通过另一阶段的CID(MS4)研究了二糖糖基阳离子[M-H•+
Mechanism of Brønsted Acid-Catalyzed Glucose Dehydration
作者:Liu Yang、George Tsilomelekis、Stavros Caratzoulas、Dionisios G. Vlachos
DOI:10.1002/cssc.201403264
日期:2015.4.24
the rate‐limiting step is the first dehydration of protonated glucose and that the majority of glucose is consumed through the HMF intermediate. We introduce a combination of 1) automatic mechanism generation with isotopic tracing experiments and 2) elementary reaction flux analysis of important paths with NMR spectroscopy and kinetic experiments to assess mechanisms. We find that the excess formic acid
Flavocoenzymes labeled with stable isotopes are important reagents for the study of flavoproteins using isotope-sensitive methods such as NMR, ENDOR, infrared, and Raman spectroscopy. We describe highly versatile one-pot methods for the preparation of riboflavin isotopomers labeled with C-13 in every desired position of the xylene moiety. The starting materials are commercially available C-13-labeled glucose samples, which are converted into riboflavin using enzymes of the oxidative pentose phosphate pathway in combination with recombinant enzymes of the riboflavin biosynthetic pathway. The overall reaction comprises six enzyme-catalyzed reaction steps for the synthesis of the vitamin and two auxiliary enzymes for in situ recycling of cofactors. The overall yields of riboflavin based on isotope-labeled glucose are 35-50%.
High yielding one-pot enzyme-catalyzed synthesis of UDP-glucose in gram scales
作者:Xueyan Ma、Joachim Stöckigt
DOI:10.1016/s0008-6215(01)00122-7
日期:2001.7
Uridine diphosphoglucose is an important cofactor of glucosylating enzymes. A simple and high yielding one-pot enzymatic synthesis of UDPG on a gram scale from glucose via hexokinase, phosphoglucomutase and UDPG pyrophosphorylase (UGPase) is described. Repetitive addition of substrate was used to avoid inhibition of UGPase. The approach allows recovery of active enzymes and their re-use. The synthesis of UDP-[4-C-13]-glucose on a 0.5 g scale resulted in a final yield of 70% and a purity of > 95% after chromatographic purification. (C) 2001 Elsevier Science Ltd. All rights reserved.