These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Thermodynamics of conformational ordering of iota-carrageenan in KCl solutions using high-sensitivity differential scanning calorimetry.
    Author: Grinberg VY, Grinberg NV, Usov AI, Shusharina NP, Khokhlov AR, de Kruif KG.
    Journal: Biomacromolecules; 2001; 2(3):864-73. PubMed ID: 11710043.
    Abstract:
    Thermodynamic properties of aqueous solutions of iota-carrageenan as affected by KCl (0.15-1.2 M) or iota-carrageenan (0.5-6 mg/mL) content were studied by high-sensitivity differential scanning calorimetry. The polysaccharide was found to undergo two consecutive cooperative conformational transitions, which can be represented by the scheme: [H2]2<-->2H2<-->4C where C is the random coil, H2 is the double helix, and [H2]2 is the double helix dimer. The first transition follows by the "all or none" mechanism. The profile of the second transition resembles that of a second-order phase transition. The parameter sigma (of order 1), estimated for this latter transition, suggests that the stacking effect in helices of iota-carrageenan is rather small. The cooperativity of the transition is mainly defined by the loop factor. Free energies of both transitions at 273 K were calculated as a function of salt concentration. These experimental data were found to agree with Manning's theory.
    [Abstract] [Full Text] [Related] [New Search]