Benassayag C, Savu L, Vallette G, Delorme J, Nunez E A
Biochim Biophys Acta. 1979 Oct 4;587(2):227-37. doi: 10.1016/0304-4165(79)90356-8.
A delipidation procedure based on treatment with charcoal at pH 3 has been applied to highly purified rat alpha 1-foetoprotein preparations. The oestrogen binding properties of the delipidated proteins have been studied with an equilibrium dialysis technique, and compared with the properties of the untreated foetal protein, as well as those of preparations reconstituted from the defatted alpha 1-foetoprotein and the removed lipids. An important increase has been evidenced for the binding levels of oestrone, oestradiol-17 beta and diethylstilboestrol by the delipidated alpha 1-foetoprotein. A reversal of this effect has been obtained by incubating the delipidated protein either with the lipids extracted from the purified alpha 1-foetoprotein or with a potent competitor of the rat alpha 1-foetoprotein-oestrogen interaction, designated as 'L', previously demonstrated and isolated from whole rat sera, and tentatively characterized as a mixture of fatty acids. Scatchard analysis of the oestrone and oestradiol-17 beta binding parameters show that the enhanced fixation of the hormones after defatting is primarily due to a two-fold increase of the apparent number of binding sites/mol alpha 1-foetoprotein. The results are interpreted in terms of the probable, at least partial, identity between the lipids closely associated with the pure alpha 1-foetoprotein and the fatty acid mixture 'L' isolated from whole sera. The possible biological role of complex interplay between oestrophilic alpha 1-foetoproteins, phenolsteroids and fatty acids in the control of oestrogen levels during development is discussed briefly.
一种基于在pH 3条件下用活性炭处理的脱脂方法已应用于高度纯化的大鼠α1-甲胎蛋白制剂。已使用平衡透析技术研究了脱脂蛋白的雌激素结合特性，并将其与未处理的胎儿蛋白以及由脱脂α1-甲胎蛋白和去除的脂质重构的制剂的特性进行了比较。已证明脱脂α1-甲胎蛋白对雌酮、雌二醇-17β和己烯雌酚的结合水平有显著提高。通过将脱脂蛋白与从纯化的α1-甲胎蛋白中提取的脂质或与大鼠α1-甲胎蛋白-雌激素相互作用的有效竞争者（称为“L”，先前已从全大鼠血清中证明并分离出来，初步鉴定为脂肪酸混合物）一起孵育，可使这种效应逆转。对雌酮和雌二醇-17β结合参数的Scatchard分析表明，脱脂后激素固定增强主要是由于每摩尔α1-甲胎蛋白结合位点的表观数量增加了两倍。结果根据与纯α1-甲胎蛋白密切相关的脂质与从全血清中分离出的脂肪酸混合物“L ”之间可能至少部分相同来解释。简要讨论了亲雌激素性α1-甲胎蛋白、酚类甾体和脂肪酸之间复杂相互作用在发育过程中控制雌激素水平方面可能的生物学作用。
