Light scattering and thermodynamic phase behavior of the system 11S globulin-κ-carrageenan-water
Light scattering and thermodynamic phase behavior of the system 11S globulin-κ-carrageenan-water
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DOI：
10.1016/s0268-005x(09)80197-5
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发表时间：
1991-03-01
影响因子：
10.7
通讯作者：
Tolstoguzov, V. B.
中科院分区：
文献类型：
--
作者：
Semenova, M. G.;Pavlovskaya, G. E.;Tolstoguzov, V. B.
11 S球蛋白（蚕豆）和κ-卡拉胶的钠形式的热力学不相容性已被研究的相行为的测量，在中等到高浓度和光散射在稀溶液中的分离阈值以下。这两种方法提供了一致的信息。对于大分子[蛋白质-蛋白质（A（22））、多糖-多糖（A（44））和蛋白质-多糖（A（24））]之间的不同类型的对相互作用，通过光散射获得的第二维里系数表明，由于存在于这些生物聚合物对的溶液中的相互排斥力，相分离（A（24））的可能性。这些力的性质（而不是大小）与κ-卡拉胶的构象无关。A（24）的温度依赖性表明熵和熵的贡献具有可比性。在该体系中，水在共存相之间的分布的一般特征与两种聚合物的相对结晶度一致。螺旋构象的κ-卡拉胶引起增加的热力学不相容性，大概是因为增加排除体积效应。
The thermodynamic incompatibility of 11S globulin (Vicia faba) and the sodium form of kappa-carrageenan has been studied by measurements of the phase behavior at moderate to high concentrations and by light scattering on dilute solutions below the separation threshold. The two approaches provide consistent information. The second virial coefficient obtained by light scattering for the different types of pair interactions between macromolecules [protein-protein (A(22)), polysaccharide-polysaccharide (A(44)) and protein-polysaccharide (A(24))] indicates the possibility of phase separation (A(24)) due to mutual exclusion forces which exist in the solution for these biopolymer pairs. The nature (but not magnitude) of these forces is independent of the conformation of kappa-carrageenan. The temperature dependence of A(24) suggests en tropic and enthalpic contributions of comparable magnitude. The general character of the water distribution between coexisting phases in this system is consistent with the relative hydrophilicities of the two polymers. Helical conformations of kappa-carrageenan give rise to increased thermodynamic incompatibility presumably because of increased excluded volume effects.