Dipyridamole Interacts with the Polar Part of Cationic Reversed Micelles in Chloroform:1H NMR and ESR Evidence

Yushmanov, Victor E.; Tabak, Marcel

doi:10.1006/jcis.1997.4925

Cited by 13 publications

(15 citation statements)

References 15 publications

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“…From the quantitative reduction of the T 1,eff relaxation time the strength and location of interaction or solubilization can be obtained [46,47]. The different strength of interactions between PG and the emulsifiers were in the order CTAB > Brij > SDS.…”

Section: Resultsmentioning

confidence: 99%

Investigating the Location of Propyl Gallate at Surfaces and Its Chemical Microenvironment by ¹H NMR

Heins

Sokolowski

Stöckmann

et al. 2007

Lipids

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The location and the resulting chemical microenvironment of the antioxidant propyl gallate (PG) was studied in micellar solutions using the cationic emulsifier cetyl trimethyl ammonium bromide (CTAB), the anionic emulsifier sodium dodecyl sulphate (SDS) and the non-ionic emulsifier Brij 58 (polyoxyethylene-20-cetyl ester). T (1) relaxation time of the aromatic protons of PG was investigated in micellar solutions and compared with that in aqueous solution in the absence of emulsifier. The relaxation time of the PG portion that is solubilized in the micelle (T (1,eff)) was calculated from the partition behavior of PG in micellar solution. From the 1D-(1)H spectrum, the alteration in the electron density of the aromatic protons and the alteration in the peak shape of the emulsifier headgroup and alkyl chain proton signals were indicative of the location of propyl gallate in the different micelles. Nuclear Overhauser effects (NOE) made it possible to deduce the exact location of PG by calculation of the relative NOEs. Marked differences were found for the location of PG in CTAB, SDS and Brij 58 micelles. PG was found to be located in the palisade layer of CTAB micelles, in the region of the polyoxyethylene chain of Brij micelles and in the Stern layer of SDS micelles. For careful study of the location of antioxidants and therefore to be able to characterize the chemical microenvironment of the antioxidants is crucial for understanding differences in antioxidant activities as a function of lipid surfaces. The application of spectroscopic methods may help to optimize the antioxidant activity to inhibit lipid oxidation at surfaces that are formed in a wide range of foods (emulsions), cosmetics, pharmaceuticals (emulsions and carrier systems) and of biological membranes (LDL-particles).

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Section: Resultsmentioning

confidence: 99%

Investigating the Location of Propyl Gallate at Surfaces and Its Chemical Microenvironment by ¹H NMR

Heins

Sokolowski

Stöckmann

et al. 2007

Lipids

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“…EPR spectra, however, does not always reveal direct information on protein-solvent interactions and the solvent dynamics, which is crucial for understanding the tertiary fold of the protein segment. The EPR power saturation method for spin-labeled protein in the presence of various paramagnetic colliders (Ni-DDTA, O 2 or CrOx) was proven very useful in studying solvent accessibility of membrane-docked protein segments 20,21,22,23 . However, such studies are not easily implemented for studying hydration of proteins and protein-protein complexes in solution, and are not feasible for probing dynamic biochemical events.…”

Section: Introductionmentioning

confidence: 99%

“…The EPR power saturation method for spin-labeled protein in the presence of various paramagnetic colliders (Ni-DDTA, O 2 or CrO x ) was proven very useful in studying solvent accessibility of membranedocked protein segments. [20][21][22][23] However, such studies are not easily implemented for studying hydration of proteins and protein-protein complexes in solution, and are not feasible for probing dynamic biochemical events. Overhauser DNP, on the other hand, is able to probe protein-solvent interactions with fast (ms) temporal resolution, and can thus monitor the solvent dynamics at specific protein sites throughout the course of protein aggregation to amyloid fibers in solution state under ambient conditions.…”

Section: Introductionmentioning

confidence: 99%

Site-specific dynamic nuclear polarization of hydration water as a generally applicable approach to monitor protein aggregation

Pavlova

McCarney

Peterson

et al. 2009

Phys. Chem. Chem. Phys.

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We present a generally applicable approach for monitoring protein aggregation by detecting changes in surface hydration water dynamics and the changes in solvent accessibility of specific protein sites, as protein aggregation proceeds in solution state. This is made possible through the Overhauser dynamic nuclear polarization (DNP) of water interacting with stable nitroxide spin labels tethered to specific proteins sites. This effect is highly localized due to the magnetic dipolar nature of the electron–proton spin interaction, with >80 % of their interaction occurring within 5 Å between the unpaired electron of the spin label and the proton of water. We showcase our tool on the aggregation of tau proteins, whose fibrillization is linked to neurodegenerative disease pathologies known as taupathies. We demonstrate that the DNP approach to monitor local changes in hydration dynamics with residue specificity and local contrast can distinguish specific and neat protein-protein packing leading to fibers from non-specific protein agglomeration or precipitation. The ability to monitor tau assembly with local, residue-specific, resolution, under ambient condition and in solution state will help unravel the mechanism and structural characteristics of the gradual process of tau aggregation into amyloid fibers, which remains unclear to this day.

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“…Uma forma de estimar os valores iniciais do tempo de correla-ção médio, bem como da anisotropia, é a partir de um espectro de RPE a uma temperatura tal que a dinâmica do marcador de spin seja rápida e a forma de linha deste espectro seja caracterizada aproximadamente por três linhas bem definidas 15 . Nesse espectro, a diferença de intensidades entre as linhas do campo central e baixo permite medir a anisotropia (N no caso de simetria axial), onde não se leva em consideração a linha para campo alto.…”

Section: Difusão Rotacional Browniana (Ipdf=0)unclassified

Simulação de espectros de ressonância paramagnética eletrônica (RPE) através do programa NLSL

Salmon¹,

Neto²,

Tabak³

et al. 2007

Quím. Nova

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Dipyridamole Interacts with the Polar Part of Cationic Reversed Micelles in Chloroform:1H NMR and ESR Evidence

Cited by 13 publications

References 15 publications

Investigating the Location of Propyl Gallate at Surfaces and Its Chemical Microenvironment by ¹H NMR

Investigating the Location of Propyl Gallate at Surfaces and Its Chemical Microenvironment by ¹H NMR

Site-specific dynamic nuclear polarization of hydration water as a generally applicable approach to monitor protein aggregation

Simulação de espectros de ressonância paramagnética eletrônica (RPE) através do programa NLSL

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Dipyridamole Interacts with the Polar Part of Cationic Reversed Micelles in Chloroform:1H NMR and ESR Evidence

Cited by 13 publications

References 15 publications

Investigating the Location of Propyl Gallate at Surfaces and Its Chemical Microenvironment by 1H NMR

Investigating the Location of Propyl Gallate at Surfaces and Its Chemical Microenvironment by 1H NMR

Site-specific dynamic nuclear polarization of hydration water as a generally applicable approach to monitor protein aggregation

Simulação de espectros de ressonância paramagnética eletrônica (RPE) através do programa NLSL

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Product

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Investigating the Location of Propyl Gallate at Surfaces and Its Chemical Microenvironment by ¹H NMR

Investigating the Location of Propyl Gallate at Surfaces and Its Chemical Microenvironment by ¹H NMR