Rozhkov S P, Borisova A G
Biofizika. 1993 Jul-Aug;38(4):590-5.
Effective thermodynamic parameters of activation of label transition between two microsurroundings in water-protein matrix (WPM) of spin-labelled molecules of serum albumin (HSA-SL) in 0.001 M phosphate buffer, pH 7.3 within concentration range of NaCl (m3) (10(-3) M to 2 M and concentration range of protein (m2) 50 to 200 mg/ml were determined. The phase transition (PT) between two structures of water in WPM is revealed within the m3 range 0.01 M to 0.1 M. It is close to the type I PT and more expressed at high protein concentrations. As m3 increases (to 0.2 M when m2 = 50 mg/ml and to 0.7 when m2 = 200 mg/ml) PT-I is transformed into PT of the critical type. This is indicated to zero values of the higher order derivatives of Gibbs energy of activation with respect to salt concentration, as well as by the maximum values of positive disjoining pressure in these points. The biological significance of this phenomenon is discussed.
在0.001 M磷酸盐缓冲液（pH 7.3）中，测定了血清白蛋白自旋标记分子（HSA-SL）在水 - 蛋白质基质（WPM）中两个微环境之间标签转变的有效热力学活化参数，其中NaCl浓度范围（m3）为10(-3) M至2 M，蛋白质浓度范围（m2）为50至200 mg/ml。在WPM中两种水结构之间的相变（PT）在m3范围0.01 M至0.1 M内被揭示。它接近I型PT，并且在高蛋白浓度下更明显。随着m3增加（当m2 = 50 mg/ml时增加到0.2 M，当m2 = 200 mg/ml时增加到0.7 M），PT-I转变为临界类型的PT。这通过活化吉布斯能量相对于盐浓度的高阶导数的零值以及这些点处正分离压力的最大值来表明。讨论了该现象的生物学意义。
