PREPARATION AND PROPERTIES OF SERUM AND PLASMA PROTEINS .32. THE INTERACTION OF HUMAN SERUM ALBUMIN WITH ZINC IONS
PREPARATION AND PROPERTIES OF SERUM AND PLASMA PROTEINS .32. THE INTERACTION OF HUMAN SERUM ALBUMIN WITH ZINC IONS
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DOI：
10.1021/ja01123a027
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发表时间：
1952-01-01
影响因子：
15
通讯作者：
GOODMAN, DS
中科院分区：
文献类型：
--
作者：
GURD, FRN;GOODMAN, DS
在异离子蛋白的0.15 M硝酸钠非缓冲溶液中研究了人血清白蛋白与锌离子的相互作用，其中加入了不同量的氢氧化钠和氯化锌。结果表明，锌离子与白蛋白中组氨酸残基的咪唑基团结合，大约以一个锌离子与一个咪唑基团的比例。将锌离子和氢离子的结合视为咪唑基团的竞争，计算了锌离子的本征结合常数。发现这个常数在相当大的范围内，每摩尔蛋白质结合的锌离子摩尔数的值不变。该常数的值不受白蛋白胍基化或重氮酯化的影响，与锌离子与咪唑相互作用测定的第一缔合常数一致。最近，人们利用二价金属离子，特别是锌离子的作用，选择性地使人血浆中的蛋白质和牛肝提取物中的蛋白质不溶。[6]用这种方法可以在很大程度上降低所用有机溶剂的浓度，或者完全不用它们来实现某些分离。4.这种技术倾向于生产更稳定的蛋白质制剂，并简化了温度控制的维护。锌盐的使用还使得分离对离子强度不太敏感，这意味着不再需要降低主体的离子强度。
The interaction of human serum albumin with zinc ions has been studied in unbuffered solutions of the isoionic protein in 0.15 M sodium nitrate to which varying quantities of sodium hydroxide and zinc chloride were added. The results have been interpreted to show that zinc ions bind to the imidazole group of the histidine residues in the albumin, approximately in the proportion of one zinc ion to one imidazole group. Treating the binding of zinc ions and of hydrogen ions as a competition for the imidazole groups, an intrinsic binding constant for zinc ions has been calculated. This constant was found not to vary over a considerable range of values for the number of moles of zinc ions bound per mole of protein. The value of the con-stant is unchanged by guanidination or diazo-esterification ofthe albumin, and was identical with the first association constant determined for the interaction of zinc ions with imidazole.Advantage has recently been taken of the action of divalent metallic ions, notably zinc ion, in selec-tivity rendering insoluble the proteins contained in human blood plasma2, 3, 4 and in extracts of bovine liver. 6 It has been possible in this way either to reduce to a great extent the concentrations of organic solvents employed, or to abolish their use entirely in achieving certain separations. 4 This technique has tended to yield more stable protein preparations, and has simplified the main-tenance of temperature control. The use of zinc salts also has rendered the separations less sensitive to ionic strength, which means that it is no longer necessary to lower the ionic strength of body