CONFIGURATIONAL TRANSITIONS IN GELATINS IN NON-AQUEOUS SOLUTIONS
CONFIGURATIONAL TRANSITIONS IN GELATINS IN NON-AQUEOUS SOLUTIONS
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DOI：
10.1021/j150580a037
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发表时间：
1959-01-01
影响因子：
--
通讯作者：
ANESEY, J
中科院分区：
文献类型：
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作者：
VEIS, A;ANESEY, J
在水溶液中，无序的明胶分子不能返回到天然胶原蛋白的有序螺旋结构。然而，由于合成多肽和一些蛋白质可以通过适当选择溶剂系统可逆地进行螺旋-卷曲转化，因此已经对明胶进行了类似的尝试。本文研究了明胶在甲酸-二甲基甲酰胺和二氯甲烷-二氯乙酸中的行为。这些研究包括（1）作为溶剂组成的函数的旋光功率和旋光色散的分析;（2）通过粘度测量描述的构型变化;和（3）通过光散射确定的聚集和降解的作用。[] 26· 6对FA中的明胶为-116，且随着DMF含量的增加而变得更正，在5%FA的DMF溶液中达到-58。在摩尔混合比FA/DMF= 1时，[a] d与FA浓度的关系图不连续。类似地，在FA/DMF= 1时，[ij]与FA浓度的曲线图中存在不连续性，当FA/DMF< 1时，[ij]急剧上升。光散射数据表明在FA-DMF混合物中没有形成聚集体。这些数据与当FA/DMF< 1时形成氢键螺旋结构的假设一致，但该螺旋与天然胶原的螺旋不同。这些数据的含义进行了讨论。
In aqueous solutions, disordered gelatin molecules cannot be returned to the ordered helical structure of native collagen. However, since synthetic polypeptides and some proteins can be made to go through the helix-coil transformation reversibly by the appropriate choice of solvent systems, a similar attempt has been made with gelatins. The behavior of gelatin in formic acid (FA)-dimethylformamide (DMF) and in ethylene dichloride-dichloroacetic acid has been examined. The studies cover (1) an analysis of the optical rotatory power and rotatory dispersion as a function of solvent composition;(2) the configurational changes as described by viscosity measurements; and (3) the roles of aggregation and degradation as determined by light scattering.[] 26· 6 is—116 for gelatin in FA and becomes more positive as the DMF content is in-creased, reaching a value of—58 at 5% FA in DMF. There is a discontinuity in a plot of [a] d vs. FA concentrationat the molar mixing ratio FA/DMF= 1. Similarly, there is a discontinuity in a plot of [] vs. FA concentrationat FA/DMF= 1, with a sharp rise in [ij] when FA/DMF< 1. The light-scattering data indicate that no aggregates are formed in the FA-DMF mixtures. These data are consistent with the assumption that a hydrogen-bonded helical structure is formed when FA/DMF< 1 but this helix is not the same as that of native collagen. Theimplications of these data are discussed.