Pd(ii)–NHC coordination-driven formation of water-soluble catalytically active single chain nanoparticles

2018 ◽  
Vol 9 (23) ◽  
pp. 3199-3204 ◽  
Author(s):  
Romain Lambert ◽  
Anne-Laure Wirotius ◽  
Sofiem Garmendia ◽  
Pierre Berto ◽  
Joan Vignolle ◽  
...  
Keyword(s):  
Suzuki Coupling ◽  
Water Soluble ◽  
Intramolecular Coordination ◽  
Single Chain ◽  
Catalytically Active

Intramolecular coordination of a linear copolymer precursor yields single chain nanoparticles (SCNP's) consisting of Pd(ii)-NHC2 crosslinks and showing a beneficial SCNP effect when used for the Suzuki coupling in water.

Solubilization of Itraconazole by Surfactants and Phospholipid-Surfactant Mixtures: Interplay of Amphiphile Structure, pH and Electrostatic Interactions

2020 ◽  
Author(s):  
Zahari Vinarov ◽  
Gabriela Gancheva ◽  
Nikola Burdzhiev ◽  
Slavka S. Tcholakova
Keyword(s):  
Nmr Spectroscopy ◽  
Electrostatic Interactions ◽  
Triazole Ring ◽  
Water Soluble ◽  
Single Chain ◽  
Surfactant Mixtures ◽  
Solubilization Capacity ◽  
Water Soluble Drugs ◽  
Hydrophobic Chain ◽  
Brick Dust

Although surfactants are frequently used in enabling formulations of poorly water-soluble drugs, the link between their structure and drug solubilization capacity is still unclear. We studied the solubilization of the “brick-dust” molecule itraconazole by 16 surfactants and 3 phospholipid:surfactant mixtures. NMR spectroscopy was used to study in more details the drug-surfactant interactions. Very high solubility of itraconazole (up to 3.6 g/L) was measured in anionic surfactant micelles at pH = 3, due to electrostatic attraction between the oppositely charged (at this pH) drug and surfactant molecules. <sup>1</sup>H NMR spectroscopy showed that itraconazole is ionized at two sites (2+ charge) at these conditions: in the phenoxy-linked piperazine nitrogen and in the dioxolane-linked triazole ring. The increase of amphiphile hydrophobic chain length had a markedly different effect, depending on the amphiphile type: the solubilization capacity of single-chain surfactants increased, whereas a decrease was observed for double-chained surfactants (phosphatidylglycerols). The excellent correlation between the chain melting temperatures of phosphatidylglycerols and itraconazole solubilization illustrated the importance of hydrophobic chain mobility. This study provides rules for selection of itraconazole solubilizers among classical single-chain surfactants and phospholipids. The basic physics underpinning the described effects suggests that these rules should be transferrable to other “brick-dust” molecules.

scholarly journals Topology and quaternary structure of pro-sucrase/isomaltase and final-form sucrase/isomaltase

1986 ◽  
Vol 237 (2) ◽  
pp. 455-461 ◽  
Author(s):  
G M Cowell ◽  
J Tranum-Jensen ◽  
H Sjöström ◽  
O Norén
Keyword(s):  
Electron Microscopy ◽  
Quaternary Structure ◽  
Functional Organization ◽  
Enzyme Complex ◽  
Single Chain ◽  
Pancreatic Duct Ligation ◽  
Duct Ligation ◽  
Catalytically Active ◽  
Identical Series ◽  
Dimeric Model

Pig sucrase/isomaltase (EC 3.2.1.48/10) was purified from intestinal microvillar vesicles prepared from animals with and without pancreatic-duct ligation to obtain the single-chain pro form and the proteolytically cleaved final form respectively. The purified enzymes were re-incorporated into phosphatidylcholine vesicles and analysed by electron microscopy after negative staining. The two forms of the enzyme were observed as identical series of characteristic projected views that could be unified in a single dimeric model, containing two sucrase and two isomaltase units. This shows a homodimeric functional organization similar to that of other microvillar hydrolases. The bulk of the dimer was separated from the membrane by a maximal gap of 3.5 nm, representing a junctional segment connecting the intramembrane section of the anchor to the catalytically active domain of sucrase/isomaltase. The enzyme complex protrudes from the membrane for a distance of up to 17 nm. From charge-shift immunoelectrophoresic studies of hydrophilic prosucrase/isomaltase and from electron microscopy of reconstituted pro-sucrase/isomaltase, there was no evidence to suggest the presence of anchoring sequences between the sucrase and isomaltase subunits.

Staphylococcus aureus: Production of Extracellular Compounds and Behavior in Foods - A Review

1989 ◽  
Vol 52 (4) ◽  
pp. 267-282 ◽  
Author(s):  
MARGARET I. HALPIN-DOHNALEK ◽  
ELMER H. MARTH
Keyword(s):  
Staphylococcus Aureus ◽  
Dairy Products ◽  
Food Poisoning ◽  
Water Soluble ◽  
Bakery Products ◽  
Single Chain ◽  
Poultry Products ◽  
Heat Stable ◽  
And Behavior ◽  
Red Meats

Growth of Staphylococcus aureus is accompanied by production of such extracellular compounds as hemolysins, nuclease, coagulase, lipase, and enterotoxins. Enterotoxins that can cause food poisoning are produced by about one-third of the coagulase-positive strains of S. aureus. The enterotoxins are a heterogeneous group of heat-stable, water-soluble, single-chain globular proteins having a molecular weight between 28,000 and 35,000 daltons. Production of enterotoxin by appropriate strains of S. aureus is affected by the nutritional quality and pH of the substrate, temperature, atmosphere, sodium chloride (and hence water activity), other chemicals, and competing microorganisms. Outbreaks of staphylococcal food poisoning most often are associated with processed red meats, poultry products (especially chicken salad), sauces, dairy products (especially cheeses), and custard- or cream-filled bakery products. Ham and associated products often are involved in as many as 30% of outbreaks of staphylococcal food poisoning. Most outbreaks result from the combined effects of contamination of the food, often through unsanitary handling, with S. aureus and holding the food at the wrong temperature thus allowing growth and synthesis of enterotoxin by the pathogen.

scholarly journals Catalytically Active N -Heterocyclic Carbene Release from Single-Chain Nanoparticles Following a Thermolysis-Driven Unfolding Strategy

2019 ◽  
Vol 40 (15) ◽  
pp. 1970033
Author(s):  
Sofiem Garmendia ◽  
Stefan B. Lawrenson ◽  
Maria C. Arno ◽  
Rachel K. O'Reilly ◽  
Daniel Taton ◽  
...  
Keyword(s):  
Single Chain ◽  
Catalytically Active

scholarly journals Surface water retardation around single-chain polymeric nanoparticles: critical for catalytic function?

2016 ◽  
Vol 7 (3) ◽  
pp. 2011-2015 ◽  
Author(s):  
Patrick J. M. Stals ◽  
Chi-Yuan Cheng ◽  
Lotte van Beek ◽  
Annelies C. Wauters ◽  
Anja R. A. Palmans ◽  
...  
Keyword(s):  
Surface Water ◽  
Functional Groups ◽  
Polymeric Nanoparticles ◽  
Water Soluble ◽  
Single Chain ◽  
Catalytic Function ◽  
Radical Polymerisation

A library of water-soluble dynamic single-chain polymeric nanoparticles (SCPN) was prepared using a controlled radical polymerisation technique followed by the introduction of functional groups, including probes at targeted positions.

With Phosphinophosphonic Acids to Nanostructured, Water-Soluble, and Catalytically Active Rhodium Clusters

2007 ◽  
Vol 46 (7) ◽  
pp. 1164-1167 ◽  
Author(s):  
Julija Glöckler ◽  
Stefan Klützke ◽  
Wolfgang Meyer-Zaika ◽  
Armin Reller ◽  
F. Javier García-García ◽  
...  
Keyword(s):  
Water Soluble ◽  
Rhodium Clusters ◽  
Catalytically Active

ChemInform Abstract: Aqueous Suzuki Coupling Reaction Catalyzed by Water-Soluble Diimine/Pd(II) Systems.

ChemInform ◽  
2009 ◽  
Vol 40 (28) ◽  
Author(s):  
Jin Zhou ◽  
Xuming Guo ◽  
Changzheng Tu ◽  
Xiaoyan Li ◽  
Hongjian Sun
Keyword(s):  
Coupling Reaction ◽  
Suzuki Coupling ◽  
Water Soluble ◽  
Suzuki Coupling Reaction

Water-Soluble Dendritic Architectures with Carbohydrate Shells for the Templation and Stabilization of Catalytically Active Metal Nanoparticles

2005 ◽  
Vol 38 (20) ◽  
pp. 8308-8315 ◽  
Author(s):  
Michael Krämer ◽  
Nelly Pérignon ◽  
Rainer Haag ◽  
Jean-Daniel Marty ◽  
Ralf Thomann ◽  
...  
Keyword(s):  
Metal Nanoparticles ◽  
Water Soluble ◽  
Active Metal ◽  
Catalytically Active
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