Thermal coagulation of serum proteins; the effects of iodoacetate, iodoacetamide, and thiol compounds on coagulation.
Thermal coagulation of serum proteins; the effects of iodoacetate, iodoacetamide, and thiol compounds on coagulation.
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血清蛋白热凝固；
DOI：
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发表时间：
1949
期刊：
影响因子：
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通讯作者：
E. Jensen
中科院分区：
文献类型：
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作者：
C. Huggins;E. Jensen
在研究热对人血清蛋白质影响的过程中，观察到在pH为7.4时，微量的碘乙酸钠完全阻止热凝血，而微量的硫醇则显著促进凝血。本文对这些观察结果进行了分析。一种蛋白质，如蛋清蛋白的热凝结被认为(1)由两个过程组成，即蛋白质与热水之间的变性反应，然后是改变后的蛋白质以颗粒形式凝集。从X射线衍射研究(2)，已经证明蛋白质的变性包括释放或产生多肽链，这些多肽链聚集在凝聚成平行的束状。这种全面的物理变化受许多因素的影响，包括溶液中的pH(3，4)和电解液的浓度(5)和性质(6，7)。许多物质可以防止蛋白质的热凝，如浓硫氰酸盐和碘(6)、日耳曼宁(S)、浓缩液中的某些糖(9，10)、胸腺核(11)以及某些脂肪酸和洗涤剂(12，13)。然而，只有洗涤剂和胸腺成核剂才能在低浓度范围内抑制凝血，而后者与碘乙酸酯不同，后者的抑制作用可被相对较低浓度的氯化钠消除(11)。由于病理学方面的影响(14)，本文中描述的大多数实验都是用正常的人血清进行的，以确保关于这个完整系统的数据。然而，当使用结晶牛血浆白蛋白、结晶鸡蛋白蛋白和人血清白蛋白的溶液时，也观察到了主要的影响；包括了对这些更简单的体系的初步实验，这些实验涉及到这种现象的机制。
In the course of studies of the effect of heat on the proteins of human serum it was observed that, at pH 7.4, minute amounts of sodium iodoacetate completely prevented thermal coagulation, while traces of mercaptans markedly enhanced the coagulation. The present paper is an analysis of these observations. The thermal coagulation of a protein, such as egg albumin, has been postulated (1) to consist of two processes, the denaturation reaction between the protein and hot water, followed by the agglutination of the altered protein in particulate form. From x-ray diffraction studies (2) it has been demonstrated that denaturation of proteins involves liberation or generation of peptide chains which aggregate on coagulation into parallel bundles. This over-all physical change is affected by many factors including pH (3, 4) and the concentration (5) and nature (6, 7) of electrolytes in the solution. A number of substances prevent thermal coagulation of proteins, such as concentrated thiocyanate and iodide (6), germanin (S), certain sugars in concentrated solution (9, lo), thymus nucleate (ll), and certain fatty acids and detergents (12, 13). However, the only agents which inhibit coagulation in the low concentration range in which iodoacetate is active are detergents and thymus nucleate, and the inhibitory effect of the latter substance, unlike that of iodoacetate, is abolished by relatively low concentrations of sodium chloride (11). Because of implications in pathology (14) most of the experiments described in this paper were carried out with normal human serum in order to secure data on this intact system. However, the principal effects were also observed when solutions of crystallized bovine plasma albumin, crystallized egg albumin, and human serum albumin were employed; preliminary experiments with these simpler systems, which bear on the mechanism of the phenomenon, are included.