The use of fluoro- and deoxy-substrate analogs to examine binding specificity and catalysis in the enzymes of the sorbitol pathway
摘要:
The carbohydrate specificity of the two enzymes that catalyze the metabolic interconversions in the sorbitol pathway, aldose reductase and sorbitol dehydrogenase, has been examined through the use of fluoro- and deoxy-substrate analogs. Hydrogen bonding has been shown to be the primary mode of interaction by which these enzymes specifically recognize and bind their respective polyol substrates. Aldose reductase has broad substrate specificity, and all of the fluoro- and deoxysugars that were examined are substrates for this enzyme. Unexpectedly, both 3-fluoro- and 4-fluoro-D-glucose were found to be better substrates, with significantly lower K-m and higher k(cat)/K-m values than those of D-glucose. A more discriminating pattern of substrate specificity is observed for sorbitol dehydrogenase. Neither the 2-fluoro nor the 2-deoxy analogs of D-glucitol were found to be substrates or inhibitors, suggesting that the 2-hydroxyl group of sorbitol is a hydrogen bond donor. The 4-fluoro and 4-deoxy analogs are poorer substrates than sorbitol, also implying a binding role for this hydroxyl group. In contrast, both 6-fluoro- and 6-deoxy-D-glucitol are very good substrates for sorbitol dehydrogenase, indicating that the primary hydroxyl group at this position is not involved in substrate recognition by this enzyme. (C) 1998 Elsevier Science Ltd. All rights reserved.
摘要描述了全部四种脱氧氟-α-d-吡喃葡萄糖基磷酸酯的合成。确定了其酸催化水解的速率常数,并且显示出氟取代在降低速率方面具有显著作用,特别是当取代邻近异头中心时。在25℃下在m HClO 4中测量的相对速率常数对于α-d-吡喃葡萄糖基磷酸酯和2-,3-,4-和6-脱氧氟衍生物分别为60.30:1.00:7.05:3.97:16.5。详细研究了2-脱氧-2-氟-α-d-吡喃葡萄糖基磷酸酯的水解,确定了4.1 eu(m反应物)和113.5 kJ.mol -1的活化熵和焓。在60°m HClO 4中的溶液中,研究了其水解的pH依赖性,并测定了单阴离子水解的速率常数(k M = 1。因此,提取了88×10 -6 s -1)和中性(k N = 6.23×10 -5 s -1)的物种。如所预期的,单阴离子的水解不受氟取代的显着影响。根据这些发现,合理化了几种机械上不同的酶利用这些氟化底物的能力或无能为力。
Enzymic aldol condensation/isomerization as a route to unusual sugar derivatives
作者:J. Robert. Durrwachter、Dale G. Drueckhammer、Kenji. Nozaki、H. Marcel. Sweers、Chi Huey. Wong
DOI:10.1021/ja00284a053
日期:1986.11
probes,* and chemical intermediate^.^ A recent review article reflects the importance of these compounds by enumerating hundreds of individual papers in the area of carbohydrate synthesis4 Traditional sources of rare or unnatural sugars have been chemical modification of natural sugars and total synthesis. The former was proven successful in many cases. However, total synthesis has evolved to a very
[EN] NEOGLYCORANDOMIZATION AND DIGITOXIN ANALOGS<br/>[FR] ALEATOIRISATION DES NEOGLYCOSIDES ET ANALOGUES DE LA DIGITOXINE
申请人:WISCONSIN ALUMNI RES FOUND
公开号:WO2006002381A1
公开(公告)日:2006-01-05
The present invention provides methods of producing libraries of compounds with enhanced desirable properties and diminished side effects as well as the compounds produced by the methods. In preferred embodiments, methods of the present invention use a universal chemical glycosylation method that employs reducing sugars and requires no protection or activation. In a preferred embodiment, the invention provides a library of neoglycoside digitoxin analogs that includes compounds with significantly enhanced cytotoxic potency toward human cancer cells and tumor-specificity, but are less potent Na+/K+-ATPase inhibitors in a human cell line than digitoxin.
Chemoenzymatic Synthesis of Fluorinated Cellodextrins Identifies a New Allomorph for Cellulose‐Like Materials**
作者:Peterson Andrade、Juan C. Muñoz‐García、Giulia Pergolizzi、Valeria Gabrielli、Sergey A. Nepogodiev、Dinu Iuga、László Fábián、Rinat Nigmatullin、Marcus A. Johns、Robert Harniman、Stephen J. Eichhorn、Jesús Angulo、Yaroslav Z. Khimyak、Robert A. Field
DOI:10.1002/chem.202003604
日期:2021.1.18
the self‐assembly of building blocks into complex hierarchical structures represents a major challenge en route to the design and preparation of soft‐matter materials with specific properties. Enzymatically synthesised cellodextrins are known to have limited water solubility beyond DP9, a point at which they self‐assemble into particles resembling the antiparallel cellulose II crystalline packing. We
了解构建块自组装成复杂分层结构的细节是设计和制备具有特定性能的软物质材料的主要挑战。已知酶法合成的纤维糊精在 DP9 之外具有有限的水溶性,此时它们会自组装成类似于反平行纤维素 II 晶体堆积的颗粒。我们通过化学酶法合成制备并表征了一系列具有不同氟化程度和取代模式的位点选择性氟化纤维糊精。考虑到纤维素 II 氢键网络的潜在破坏,我们制备并表征了多重 6-氟化纤维糊精。此外,还合成了一系列单位点选择性氟化纤维糊精,以评估每条链添加一个氟原子对结构的影响。结合先进的核磁共振波谱和显微镜方法,对这些材料在不同长度尺度上的结构表征表明,6-氟化供体基质产生了多个6-氟化纤维糊精链,这些链组装成具有形态和结晶特征以及分子间相互作用的颗粒,这对于类纤维素材料来说是前所未有的。
Anomeric Selectivity of Trehalose Transferase with Rare <scp>l</scp>-Sugars
作者:Luuk Mestrom、Stefan R. Marsden、Hessel van der Eijk、Jesper U. Laustsen、Cy M. Jeffries、Dmitri I. Svergun、Peter-Leon Hagedoorn、Isabel Bento、Ulf Hanefeld
DOI:10.1021/acscatal.0c02117
日期:2020.8.7
glycosyltransferases catalyze the formation of glycosidic bonds between nucleotide sugar donors and carbohydrate acceptors. The anomeric selectivity of trehalose transferase from Thermoproteus uzoniensis was investigated for both d- and l-glycopyranose acceptors. The enzyme couples a wide range of carbohydrates, yielding trehalose analogues with conversion and enantioselectivity of >98%. The anomeric selectivity inverts
Chemoenzymatic Synthesis of Trehalose Analogues: Rapid Access to Chemical Probes for Investigating Mycobacteria
作者:Bailey L. Urbanek、Douglas C. Wing、Krystal S. Haislop、Chelsey J. Hamel、Rainer Kalscheuer、Peter J. Woodruff、Benjamin M. Swarts
DOI:10.1002/cbic.201402288
日期:2014.9.22
Trehalose tools for TB: A one‐step chemoenzymatic method for the rapid and efficient synthesis of trehalose analogues was developed. This method enabled facile preparation and administration of a trehalose‐based probe for detecting mycobacteria, which might enable the development of new diagnostic tools for tuberculosis (TB) research.