THERMODYNAMIC STUDY OF THE APOMYOGLOBIN STRUCTURE
THERMODYNAMIC STUDY OF THE APOMYOGLOBIN STRUCTURE
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DOI：
10.1016/0022-2836(88)90525-6
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发表时间：
1988-07-05
影响因子：
5.6
通讯作者：
KUTYSHENKO, VP
中科院分区：
文献类型：
--
作者：
GRIKO, YV;PRIVALOV, PL;KUTYSHENKO, VP
通过扫描微量热法、粘度法、核磁共振和圆二色光谱法，以及静电滴定法和量热滴定法，对抹香鲸脱辅基肌红蛋白在不同pH和温度的溶液中进行了热力学研究。结果表明，脱辅基肌红蛋白在pH接近中性的溶液中具有致密而独特的空间结构，并具有延伸的疏水核。该结构在约 30°C 时最为稳定，并在从此温度加热或冷却时可逆地分解。这种结构的分解过程是高度协作的，可以被视为蛋白质的两种宏观状态（天然状态和变性状态）之间的转变。与由紧实度和椭圆度的确定值指定的天然状态相反，脱辅基肌红蛋白变性状态的紧实度和椭圆度很大程度上取决于pH；随着pH值降低到4·0以下，这些参数逐渐接近无规卷曲的值。
Sperm whale apomyoglobin has been studied thermodynamically in solutions with different pH and temperature by scanning microcalorimetry, viscosimetry, nuclear magnetic resonance and circular dichroism spectrometry, and by electrometric and calorimetric titration.It has been shown that apomyoglobin in solutions with pH close to neutral has a compact and unique spatial structure with an extended hydrophobic core. This structure is maximally stable at about 30 °C and breaks down reversibly both upon heating or cooling from this temperature. The process of breakdown of this structure is highly co-operative and can be regarded as a transition between two macroscopic states of protein, the native and denatured states. In contrast to the native state, which is specified by definite values of compactness and ellipticity, the compactness and ellipticity of the denatured state of apomyoglobin depend strongly on pH; with a decrease of pH below 4·0, these parameters gradually approach the values of the random coil.