HYDROPHOBIC INTERACTION AND A MODEL FOR ELASTICITY OF ELASTIN
HYDROPHOBIC INTERACTION AND A MODEL FOR ELASTICITY OF ELASTIN
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DOI：
10.1002/bip.1978.360170311
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发表时间：
1978-01-01
期刊：
影响因子：
2.9
通讯作者：
GOSLINE, JM
中科院分区：
文献类型：
--
作者：
GOSLINE, JM
本文用微量热法研究了牛项韧带类橡胶蛋白弹性蛋白弹性过程的热力学。在室温下，水溶胀弹性蛋白的伸展释放的可逆热显然比储存的弹性能大得多，表明伸展的大的负内能变化。测量的内部能量变化与存储的能量的比率与延伸成反比，并且在22 ° C处变化。C对于2%的延伸是-91，对于70%的延伸是-3。在2 - 65 ℃的范围内，内能变化也随温度显著变化。在低温下为大的负值，并逐渐变得更正，直到约65 ℃。C是零。所测得的内部能量变化的温度依赖性几乎是相同的内部能量变化与疏水相互作用的破坏的温度依赖性，并建议，所测得的内部能量变化可以完全归因于水的吸收到非极性基团的弹性蛋白网络。基于这一假设的计算表明，与此溶剂-聚合物过程相关的自由能变化是大的和积极的。水吸附到疏水基团上显然有助于弹性蛋白的弹性，特别是在小于约70%的延伸时。这种弹性机制的影响进行了讨论的弹性蛋白结构的随机网络模型。
The thermodynamics of the elastic process in the rubberlike protein elastin [from the ligamentum nuchae of cattle] were investigated by microcalorimetry. The reversible heat liberated on the extension of water-swollen elastin at room temperature apparently is much larger than the stored elastic energy, indicating a large, negative internal energy change for stretching. The ratio of the measured internal energy change to the stored energy varies inversely with extension, and at 22.degree. C it is -91 for 2% extension and -3 for 70% extension. The internal energy change also varies dramatically with temperature over the range of 2-65.degree. C, being large and negative at low temperatures and becoming gradually more positive until at about 65.degree. C it is zero. The temperature dependence for the measured internal energy change is virtually identical to the temperature dependence for internal energy changes associated with the breaking of hydrophobic interactions, and it is suggested that the measured internal energy change can be attributed entirely to the absorption of water onto nonpolar groups in the elastin network. Calculations based on this assumption indicate that the free-energy change associated with this solvent-polymer process is large and positive. The absorption of water onto hydrophobic groups apparently contributes to the elasticity of elastin, particularly at extensions of less than about 70%. The implications of this elastic mechanism are discussed in terms of the random-network model for elastin structure.