Interactions of some amino acids and glycine peptides with aqueous sodium dodecyl sulfate and cetyltrimethylammonium bromide at T=298.15 K: a volumetric approach
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Title |
Interactions of some amino acids and glycine peptides with aqueous sodium dodecyl sulfate and cetyltrimethylammonium bromide at T=298.15 K: a volumetric approach
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Creator |
SINGH, SREELEKHA K
KUNDU, AGNITA NAND KISHORE |
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Subject |
electrostriction
polypeptides solutions surface active agents |
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Description |
The apparent molar volumes Vφ of glycine, alanine, valine, leucine, and lysine have been determined in aqueous solutions of 0.05, 0.5, 1.0 mol · kg−1 sodium dodecyl sulfate (SDS) and 1.0 mol · kg−1 cetyltrimethylammonium bromide (CTAB) by density measurements at T=298.15 K. The apparent molar volumes have also been determined for diglycine and triglycine in 1 mol · kg−1 SDS and CTAB solutions. These data have been used to calculate the infinite dilution apparent molar volumes V20 for the amino acids and peptides in aqueous SDS and CTAB and the standard partial molar volumes of transfer (ΔtrV2,m0) of the amino acids and peptides to these aqueous surfactant solutions. The linear correlation of V20 for a homologous series of amino acids has been utilized to calculate the contribution of the charged end groups (NH3+, COO−), CH2 group and other alkyl chains of the amino acids to V20. The results on the partial molar volumes of transfer from water to aqueous SDS and CTAB have been interpreted in terms of ion–ion, ion–polar and hydrophobic–hydrophobic group interactions. The volume of transfer data suggests that ion–ion or ion–hydrophilic group interactions of the amino acids and peptides are stronger with SDS compared to those with CTAB. Comparison of the hydration numbers of amino acids calculated in the present studies with those in other solvents from literature shows that these numbers are almost the same at 1 mol · kg−1 level of the cosolvent/cosolute. Increasing molality of the cosolvent/cosolute beyond 1 mol · kg−1 lowers the hydration number of the amino acids due to increased interactions with the solvent and reduced electrostriction.
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Publisher |
Elsevier
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Date |
2009-03-02T09:30:16Z
2011-11-25T18:21:07Z 2011-12-26T13:06:45Z 2011-12-27T05:54:45Z 2009-03-02T09:30:16Z 2011-11-25T18:21:07Z 2011-12-26T13:06:45Z 2011-12-27T05:54:45Z 2004 |
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Type |
Article
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Identifier |
The Journal of Chemical Thermodynamics 36(1), 7-16
0021-9614 http://dx.doi.org/10.1016/j.jct.2003.09.010 http://hdl.handle.net/10054/840 http://dspace.library.iitb.ac.in/xmlui/handle/10054/840 |
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Language |
en
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