Proton NMR chemical shifts of solvent water in aqueous solutions of monosubstituted ammonium compounds

Bhanumathi, R; Vijayalakshamma, SK

doi:10.1021/j100410a040

Cited by 16 publications

(7 citation statements)

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“…There are generally two types of solutes in terms of changing the water structure: structure former agents that are defined as solutes that increase the intact water population and structure breaker agents that decrease the water structure by increasing the broken water population [12,13]. The effect of the structure breaker solutes is similar to the effect caused by increasing the temperature of the solution [12,13]. The terms "kosmotrope" (order-maker) and "chaotrope" (disorder-maker) originally denoted solutes that stabilized, or destabilized respectively, proteins and membranes.…”

Section: Introductionmentioning

confidence: 99%

Effect of urea on bovine serum albumin in aqueous and reverse micelle environments investigated by small angle X-ray scattering, fluorescence and circular dichroism

et al. 2004

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The influence that urea has on the conformation of water-soluble globular protein, bovine serum albumin (BSA), exposed directly to the aqueous solution as compared to the condition where the macromolecule is confined in the Aerosol-OT (AOT-sodium bis-2-ethylhexyl sulfosuccinate)/n-hexane/water reverse micelle (RM) is addressed. Small angle X-ray scattering (SAXS), tryptophan (Trp) fluorescence emission and circular dichroism (CD) spectra of aqueous BSA solution in the absence and in the presence of urea (3M and 5M) confirm the known denaturating effect of urea in proteins. The loss of the globular native structure is observed by the increase in the protein maximum dimension and gyration radius, through the Trp emission increase and maximum red-shift as well as the decrease in α-helix content. In RMs, the Trp fluorescence and CD spectra show that BSA is mainly located in its interfacial region independently of the micellar size. Addition of urea in this BSA/RM system also causes changes in the Trp fluorescence (emission decrease and maximum red-shift) and in the BSA CD spectra (decrease in α-helix content), which are compatible with the denaturation of the protein and Trp exposition to a more apolar environment in the RM. The fact that urea causes changes in the protein structure when it is located in the interfacial region (evidenced by CD) is interpreted as an indication that the direct interaction of urea with the protein is the major factor to explain its denaturating effect.

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Section: Introductionmentioning

confidence: 99%

Effect of urea on bovine serum albumin in aqueous and reverse micelle environments investigated by small angle X-ray scattering, fluorescence and circular dichroism

et al. 2004

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“…At higher concentration, urea behaves like a water-structure breaker, destroys the long range order characteristics of water and reduces the degree of water-water hydrogen bonding without replacing these interactions by strong urea-water hydrogen bonds. The effect of water structure breakers is similar to that caused by increase in temperature, 42 hence increase in cmc has been observed at higher concentration of urea and thiourea. It is apparent that thiourea has a more pronounced water structure breaking property 40,43 compared to urea, which is also an important factor for increasing the cmc more with addition of thiourea in comparison to latter.…”

Section: Effect Of Additives On Cmcmentioning

confidence: 55%

Effect of Inorganic Salts and Ureas on the Micellization Behavior of Antidepressant Drug Imipramine Hydrochloride at Various Concentrations and Temperatures

Kabir-ud-Din¹,

Малик²,

Abdul³

et al. 2012

Acta Physico-Chimica Sinica

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In the present study we report the micellization behavior of imipramine hydrochloride (IMP) in absence and presence of different concentrations of inorganic salts (LiCl, NaF, NaCl, NaBr, and KCl) and ureas (urea and thiourea) over the temperature range from 288.15 to 303.15 K. The critical micellization concentrations (cmc) of drug and drug + additive systems were determined by conductometric technique. With increasing temperature the cmc first increases then decreases. Maximum cmc values were obtained at 293.15 K with or without additives. In presence of inorganic salts the cmc value decreases which is explained on the basis of nature and ion size of the added ion. Urea and thiourea also decrease the cmc at low concentrations (0.2 mmol •L-1 urea and 0.1 mmol •L-1 thiourea), but, at higher concentrations, increase in cmc is observed. The related thermodynamic parameters are also evaluated and discussed.

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“…The disruption of the water structure by urea may increase the hydration of polar head groups of amphiphiles, thereby enhancing the solubility of unaggregated monomers. The effect of water-structure breakers is similar to that caused by an increase in temperature [49], hence an increase in the CMC has been observed at higher concentrations of urea and thiourea. As thiourea is considered a better waterstructure breaker [50], increase in CMC is greater with its addition.…”

Section: Effect Of Additives On Cmcmentioning

confidence: 66%

Effect of Temperature, Salts and Ureas on the Association Behavior of an Amphiphilic Phenothiazine Drug Promethazine Hydrochloride

Kabir-ud-Din

Rub

Naqvi

2012

J Surfact & Detergents

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Association behavior of an amphiphilic phenothiazine drug promethazine hydrochloride in the presence of inorganic salts (LiCl, NaF, NaCl, NaBr, and KCl) and ureas (urea and thiourea) has been studied conductometrically at different additive concentrations (0–100 mmol kg−1) and temperatures (293.15–308.15 K). The critical micelle concentration (CMC) values showed an inverted U‐shaped behavior with temperature; the maximum being at 298.15 K with or without additives. The inorganic salts decreased the CMC which is explained on the basis of nature and ion size. Ureas decreased the CMC at low concentration (0.2 mmol kg−1 urea and 0.1 mmol kg−1 thiourea) but, at higher concentrations, an increase in CMC was observed with both the additives. Relevant thermodynamic parameters were also evaluated and discussed on the basis of the nature of particular types of the additives. The thermodynamic parameters suggest dehydration of the hydrophobic part of the drug at higher temperatures.

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Proton NMR chemical shifts of solvent water in aqueous solutions of monosubstituted ammonium compounds

Cited by 16 publications

References 0 publications

Effect of urea on bovine serum albumin in aqueous and reverse micelle environments investigated by small angle X-ray scattering, fluorescence and circular dichroism

Effect of urea on bovine serum albumin in aqueous and reverse micelle environments investigated by small angle X-ray scattering, fluorescence and circular dichroism

Effect of Inorganic Salts and Ureas on the Micellization Behavior of Antidepressant Drug Imipramine Hydrochloride at Various Concentrations and Temperatures

Effect of Temperature, Salts and Ureas on the Association Behavior of an Amphiphilic Phenothiazine Drug Promethazine Hydrochloride

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