Three‐in‐one: Miniature Models of Natural Acyl‐transfer Systems Enable Vector‐selective Reaction on the Primary Side of Cyclodextrins

2021 ◽  
Author(s):  
De-Qi Yuan ◽  
Tatsuro Tominaga ◽  
Koki Fukuda ◽  
Kazutaka Koga ◽  
Makoto Fukudome
Keyword(s):  
Acyl Transfer ◽  
Selective Reaction

Cytochemical Localization of Polysaccharides in Diplodia Maydis With Thiosemicarbazide : Evaluation of Three Fixatives For Pa:Tsc:Os Reaction

1976 ◽  
Vol 34 ◽  
pp. 48-49 ◽  
Author(s):  
Judith A. Murphy ◽  
Mary R. Thompson ◽  
A.J. Pappelis
Keyword(s):  
Reaction Center ◽  
Osmium Tetroxide ◽  
Periodic Acid ◽  
Cytochemical Localization ◽  
Thin Sections ◽  
Selective Reaction ◽  
Amorphous Character

In an attempt to identify polysaccharide components in thin sections of D. maydis, procedures were employed such that a PAS localization could be carried out. Three different fixatives were evaluated ie. glutaraldehyde, formaldehyde and paraformaldehyde. These were used in conjunction with periodic acid (PA), thiosemicarbazide(TSC), and osmium tetroxide(Os) to localize polysaccharides in V. maydis using a pre-embedded reaction procedure. Polysaccharide localization is based on the oxidation of vic-glycol groups by PA, and the binding of TSC as a selective reaction center for the formation of osmium black. The reaction product is sufficiently electron opaque, insoluble in lipids, not altered when tissue is embedded, and has a fine amorphous character.

scholarly journals Mechanistic Study on Facet-Dependent Deposition of Metal Nanoparticles on Decahedral-Shaped Anatase Titania Photocatalyst Particles

Catalysts ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 542 ◽  
Author(s):  
Kenta Kobayashi ◽  
Mai Takashima ◽  
Mai Takase ◽  
Bunsho Ohtani
Keyword(s):  
Mechanistic Study ◽  
Phase Reaction ◽  
Surface Charges ◽  
Platinum Nanoparticle ◽  
Nanoparticle Deposition ◽  
Selective Reaction ◽  
Anatase Titania ◽  
Deposition Density ◽  
Titania Photocatalyst ◽  
Source Materials

Facet-selective gold or platinum-nanoparticle deposition on decahedral-shaped anatase titania particles (DAPs) exposing {001} and {101} facets via photodeposition (PD) from metal-complex sources was reexamined using DAPs prepared with gas-phase reaction of titanium (IV) chloride and oxygen by quantitatively evaluating the area deposition density on {001} and {101} and comparing with the results of deposition from colloidal metal particles in the dark (CDD) or under photoirradiation (CDL). The observed facet selectivity, more or less {101} preferable, depended mainly on pH of the reaction suspensions and was almost non-selective at low pH regardless of the deposition method, PD or CDL, and the metal-source materials. Based on the results, the present authors propose that facet selectivity is attributable to surface charges (zeta potential) depending on the kind of facets, {001} and {101}, and pH of the reaction mixture and that this concept can explain the observed facet selectivity and possibly the reported facet selectivity without taking into account facet-selective reaction of photoexcited electrons and positive holes on {101} and {001} facets, respectively.

scholarly journals The relation of acyl transfer to the overall reaction of thiolase I from porcine heart.

1981 ◽  
Vol 256 (14) ◽  
pp. 7371-7377
Author(s):  
H.F. Gilbert ◽  
B.J. Lennox ◽  
C.D. Mossman ◽  
W.C. Carle
Keyword(s):  
Acyl Transfer ◽  
Porcine Heart

Two-Dimensional Lateral Heterostructures Made by Selective Reaction on a Patterned Monolayer MoS2 Matrix

2021 ◽  
Author(s):  
Xuewen Wang ◽  
Bolun Wang ◽  
Yonghuang Wu ◽  
Enze Wang ◽  
Hao Luo ◽  
...  
Keyword(s):  
Two Dimensional ◽  
Monolayer Mos2 ◽  
Selective Reaction

Development of a solid-phase extraction – spectrofluorimetric method for trace glutathione determination

2011 ◽  
Vol 89 (4) ◽  
pp. 517-523 ◽  
Author(s):  
Ke-Jing Huang ◽  
Cong-Hui Han ◽  
Ying-Ying Wu ◽  
Chao-Qun Han ◽  
De-Jun Niu ◽  
...  
Keyword(s):  
Solid Phase Extraction ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Signal To Noise Ratio ◽  
Calibration Graph ◽  
Extraction Column ◽  
Phase Extraction ◽  
Selective Reaction ◽  
Spectrofluorimetric Method ◽  
Relative Standard

A simple and efficient solid-phase extraction – spectrofluorimetric method has been developed to determine glutathione (GSH). Fluorescent probe N-(4,4-difluoro-5,7-dimethyl-4-bora-3a,4a-diaza-s-indacene-3-yl)methyl)iodoacetamide (BODIPY Fl-C1-IA) was used as the derivatization reagent. The procedure was based on a BODIPY Fl-C1-IA selective reaction with GSH to form the highly fluorescent product BODIPY Fl-C1-IA–GSH, using a solid-phase extraction column and spectrofluorimetric determination. The variables affecting analytical performance were studied and optimized. The calibration graph using the preconcentration system for GSH was linear over the range of 1–200 nmol/L with a limit of detection of 0.05 nmol/L (signal-to-noise ratio = 3). The relative standard deviation for six replicate determinations of GSH at the 100 nmol/L concentration level was 3.9%. The method was applied to water samples and average recoveries between 87.5% and 111.5% were obtained for spiked samples.

A Density Functional Theory Study on the Ring-Opening Polymerization of D-Lactide Catalyzed by a Bifunctional-Thiourea Catalyst

2009 ◽  
Vol 62 (2) ◽  
pp. 157 ◽  
Author(s):  
Rong-Xiu Zhu ◽  
Ruo-Xi Wang ◽  
Dong-Ju Zhang ◽  
Cheng-Bu Liu
Keyword(s):  
Density Functional Theory ◽  
Ring Opening ◽  
Density Functional ◽  
Population Analysis ◽  
Density Functional Theory Calculations ◽  
Ring Opening Polymerization ◽  
Acyl Transfer ◽  
Frontier Molecular Orbital ◽  
Functional Theory ◽  
Elimination Pathway

The thiourea-catalyzed methanolysis of d-lactide, a model system for the initiation and propagation of the organocatalyzed ring-opening polymerization (ROP) of lactide, has been studied by performing density functional theory calculations. Both the catalyzed and uncatalyzed reactions are explored along two possible pathways: one involves the stepwise addition–elimination pathway and the other is related to the concerted pathway. It is found that the reaction without the presence of the catalyst is difficult because the barrier involved is as high as 176 kJ mol–1. With the aid of a thiourea catalyst, the barrier is reduced to 88 kJ mol–1 with a preference for the stepwise addition–elimination mechanism over the concerted one. The role of the catalyst has been rationalized by analyzing the frontier molecular orbital interactions between the catalyst and substrates and by performing natural population analysis. Finally, another mechanism involving acyl transfer is discussed for the thiourea-catalyzed ROP.

Cerium-Based M4L4Tetrahedra as Molecular Flasks for Selective Reaction Prompting and Luminescent Reaction Tracing

2014 ◽  
Vol 20 (8) ◽  
pp. 2224-2231 ◽  
Author(s):  
Yang Jiao ◽  
Jian Wang ◽  
Pengyan Wu ◽  
Liang Zhao ◽  
Cheng He ◽  
...  
Keyword(s):  
Selective Reaction

Transfer of arachidonic acid from phosphatidylcholine to phosphatidylethanolamine during storage of human platelets for 5 days

1990 ◽  
Vol 68 (1) ◽  
pp. 117-122 ◽  
Author(s):  
Julie Lacasse ◽  
Rosalind S. Labow ◽  
Morris Kates ◽  
George A. Adams
Keyword(s):  
Arachidonic Acid ◽  
Storage Conditions ◽  
Phospholipid Metabolism ◽  
Human Platelets ◽  
Acyl Transfer ◽  
Acid Uptake ◽  
Molar Composition ◽  
Platelet Storage ◽  
Head Groups ◽  
Glycerol Uptake

Human platelets are routinely stored for 5 days prior to transfusion, but they deteriorate during storage. Since very little information is available concerning the effect of storage on platelet phospholipid metabolism, the biosynthesis and remodelling of platelet phospholipids were studied. Platelets were incubated separately with [14C]glycerol, [14C]arachidonic acid, or a mixture of [14C]glycerol and [3H]arachidonic acid, and stored in a platelet storage medium at 22 °C. Maximum glycerol uptake (20%) was attained after 6 h. [14C]Glycerol was incorporated into phosphatidylcholine, phosphatidylethanolamine, and phosphatidylinositol, and to a much lesser extent phosphatidylserine, under storage conditions for 5 days. The distribution of the initial arachidonic acid uptake was not as would be expected based on the molar composition of endogenous phospholipids. The arachidonic acid (75%) which was taken up within 10 min of incubation distributed 55% into the phosphatidylcholine and only 14% into the phosphatidylethanolamine; the molar composition is actually 18% phosphatidylcholine and 47% phosphatidylethanolamine. During storage, there was a continuous transfer of the radiolabeled arachidonic acid from phosphatidylcholine to phosphatidylethanolamine until, after 5 days, the distribution of arachidonic acid was identical to the endogenous distribution. In contrast, no change in the glycerol incorporation pattern was detected during storage. This suggested that the mechanism for arachidonic acid redistribution was not through exchange of polar head groups, but through acyl transfer of arachidonic acid from phosphatidylcholine to phosphatidylethanolamine.Key words: human, platelet, storage, arachidonate, phospholipids.

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