37074-90-1Relevant articles and documents
Total synthesis of agalloside, isolated from: Aquilaria agallocha, by the 5-O-glycosylation of flavan
Arai, Midori A.,Yamaguchi, Yumi,Ishibashi, Masami
, p. 5025 - 5032 (2017/07/10)
Agalloside (1) is a neural stem cell differentiation activator isolated from Aquilaria agallocha by our group using Hes1 immobilized beads. We conducted the first total synthesis of agalloside (1) via the 5-O-glycosylation of flavan 25 using glycosyl fluoride 20 in the presence of BF3·Et2O. Subsequent oxidation with DDQ to flavanone 2 and deprotection successively provided agalloside (1). This synthetic strategy holds promise for use in the synthesis of 5-O-glycosylated flavonoids. The synthesized agalloside (1) accelerated neural stem cell differentiation, which is a result comparable to that for the naturally occurring compound 1.
Synthesis of uniformly deuterated n-dodecyl-β -d-maltoside (d39 -DDM) for solubilization of membrane proteins in TROSY NMR experiments
Hiruma-Shimizu, Kazumi,Kalverda, Arnout P.,Henderson, Peter J. F.,Homans, Steve W.,Patching, Simon G.
, p. 737 - 743 (2015/02/19)
This work reports the first synthesis of uniformly deuterated n-dodecyl-β -D-maltoside (d39-DDM). DDM is a mild non-ionic detergent often used in the extraction and purification of membrane proteins and for solubilizing them in experimental studies of their structure, dynamics and binding of ligands. We required d39-DDM for solubilizing large α-helical membrane proteins in samples for [15N-1H]TROSY (transverse relaxation-optimized spectroscopy) NMR experiments to achieve the highest sensitivity and best resolved spectra possible. Our synthesis of d39-DDM used d7-D-glucose and d25-n-dodecanol to introduce deuterium labelling into both the maltoside and dodecyl moieties, respectively. Two glucose molecules, one converted to a glycosyl acceptor with a free C4 hydroxyl group and one converted to a glycosyl donor substituted at C1 with a bromine in the α-configuration, were coupled together with an α(1 → 4) glycosidic bond to give maltose, which was then coupled with n-dodecanol by its substitution of a C1 bromine in the α-configuration to give DDM. 1H NMR spectra were used to confirm a high level of deuteration in the synthesized d39-DDM and to demonstrate its use in eliminating interfering signals from TROSY NMR spectra of a 52-kDa sugar transport protein solubilized in DDM.
Kinetic analysis of β-phosphoglucomutase and its inhibition by magnesium fluoride
Golicnik, Marko,Olguin, Luis F.,Feng, Guoqiang,Baxter, Nicola J.,Waltho, Jonathan P.,et al.
experimental part, p. 1575 - 1588 (2009/07/30)
The isomerization of β-glucose-1 -phosphate (βG1 P) to β-glucose-6-phosphate (G6P) catalyzed by β-phosphoglucomutase (βPGM) has been examined using steady- and presteady-state kinetic analysis. In the presence of low concentrations of β-glucose-1,6- bisphosphate (βG16BP), the reaction proceeds through a Ping Pong Bi Bi mechanism with substrate inhibition (K cat = 65 s -1 , K βG1P = 15 μM, K βG1P = 0.7 μM, K i = 122 μM). If αG16BP is used as a cofactor, more complex kinetic behavior is observed, but the nonlinear progress curves canbe fit to reveal further catalytic parameters (k cat = 74 s-1 , K βG1P = 15 μM, K βG16BP = 0.8 μM, K i = 122 μM, K αG16BP = 91μM for productive binding, K αG16BP = 21 μM for unproductive binding). These data reveal that variations in the substrate structure affect transition-state affinity (approximately 140 000-fold in terms of rate acceleration) substantially more than ground-state binding (110-fold in terms of binding affinity). When fluoride and magnesium ions are present, time-dependent inhibition of the βPGM is observed. The concentration dependence of the parameters obtained from fitting these progress curves shows that a βG1 P-MgF 3- βPGM inhibitory complex is formed under the reaction conditions. The overall stability constant for this complex is approximately 2 × 10 -16 M 5 and suggests an affinity of the MgF 3 - moiety to this transition-state analogue (TSA) of ≤70 nM. The detailed kinetic analysis shows how a special type of TSA that does not exist in solution is assembled in the active site of an enzyme. Further experiments show that under the conditions of previous structural studies, phosphorylated glucose only persists when bound to the enzyme as the TSA. The preference for TSA formation when fluoride is present, and the hydrolysisof substrates when it is not, rules out the formation of a stable penta valent phosphorane intermediate in the active site of βPGM.
