Apolipoprotein A-I binds to a family of bovine seminal plasma proteins.
Apolipoprotein A-I binds to a family of bovine seminal plasma proteins.
复制标题
载脂蛋白 A-I 与牛精浆蛋白家族结合。
DOI：
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发表时间：
1989
影响因子：
4.8
通讯作者：
A. Chapdelaine
中科院分区：
文献类型：
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作者：
P. Manjunath;Y. Marcel;J. Uma;N. Seidah;M. Chrétien;A. Chapdelaine
牛精浆含有四种类似的酸性蛋白，以前被称为BSP（牛精浆）-A1, BSP- a2， BSP- a3和BSP-30- kda，当添加到垂体细胞培养物中时，会立即分泌促性腺激素（卵泡激素和尿路激素）。然而，当在培养基中加入小牛或马的血清时，促性腺激素的分泌完全被阻止。当BSP蛋白含量达到200微克/毫升时，这种效应被观察到，而在血清培养基中存在超过200微克/毫升的BSP蛋白时，促性腺激素继续释放。这可以解释为血清中存在一种与BSP蛋白结合的因子，阻止了它们的作用。使用125i标记的BSP-A1、-A2、-A3或-30-kDa蛋白进行点印迹实验，在所有测试的血清（包括人血清）中均检测到该结合因子。因此，通过BSP-A1/- a2 -琼脂糖柱亲和层析从人血清中分离出这种结合因子是很有意义的。通过以下标准鉴定纯化的结合因子为载脂蛋白a - i (apoA-I):(a)其分子质量为27,000道尔顿，(b)氨基酸组成与apoA-I相似，(c)该结合因子氨基末端的前25个残基与apoA-I相同，(d)该结合因子在apoA-I的放射免疫测定中发生交叉反应。此外，BSP蛋白还结合纯化血浆apoA-I和与高密度脂蛋白相关的apoA-I。ApoA-I是血浆高密度脂蛋白的主要蛋白，在脂质转运和代谢中起重要作用。因此，牛精浆蛋白与apoA-I的结合提示脂蛋白功能具有一定的生理意义，反之亦然。
Bovine seminal plasma contains four similar acidic proteins, previously designated as BSP (bovine seminal plasma)-A1, BSP-A2, BSP-A3, and BSP-30-kDa, that when added to pituitary cell cultures result in the immediate secretion of gonadotropins (follitropin and lutropin). However, when calf or horse serum was included in the culture medium the secretion of gonadotropins was completely prevented. This effect was seen at levels up to 200 micrograms of BSP protein/ml while the presence of more than 200 micrograms of BSP protein/ml in the serum medium continued to release gonadotropins. This could be explained by the presence in the sera of a binding factor to the BSP proteins which prevents their action. This binding factor has been detected in all the sera tested, including human serum, in dot-blot experiments using 125I-labeled BSP-A1, -A2, -A3, or -30-kDa protein. Thus, it was of interest to isolate this binding factor from human serum by affinity chromatography on a column of BSP-A1/-A2-agarose. The purified binding factor was then identified as apolipoprotein A-I (apoA-I) by the following criteria: (a) it has a molecular mass of 27,000 daltons, (b) the amino acid composition is similar to apoA-I, (c) the first 25 residues at the amino-terminal end of this binding factor are identical to apoA-I, and (d) the binding factor cross-reacts in the radioimmunoassay of apoA-I. Furthermore, BSP proteins also bind to purified plasma apoA-I and apoA-I associated with high density lipoprotein. ApoA-I is the major protein of plasma high density lipoprotein and plays an important role in lipid transport and metabolism. Thus, the binding of bovine seminal plasma proteins to apoA-I suggests some physiological significance in lipoprotein function or vice versa.