Russell J T, Thorn N A
Biochim Biophys Acta. 1977 Apr 25;491(2):398-408. doi: 10.1016/0005-2795(77)90282-3.
An acidic calcium-binding protein was isolated from the soluble fraction of the homogenate of ox neurohypophyses. The protein has a molecular weight of 35 000 and a subunit weight of 15 000. The purification procedure involved ammonium sulphate fractionation, DEAE-cellulose chromatography and gel filtration on Sephadex G-100 and Sephadex G-50. Conventional and sodium dodecyl sulfate-polyacrylamide gel electrophoresis demonstrated it to be a protein distinct from the S-100 protein and the soluble hormone-binding proteins (neurophysins) abundant in the neurohypophysis. This appears to be the only Ca2+-binding protein in the soluble part of the homogenate, with an apparent Kdiss for Ca2+ of 1.1 X 10(-5) M (at 22 degrees C) and a binding capacity of 2 mol of calcium per mol of protein. Two different Ca2+-binding proteins of molecular weights 16 500 and 68 000, respectively, were identified in the sodium-deoxycholate-soluble proteins from an ox neurohypophysial microsome fraction. One of them (the former) has been isolated in high purity by DEAE-cellulose chromatography and gel filtration on Sephadex G-200. This protein binds 4 mol of calcium per mol of protein with an apparent Kdiss of 1.0 X 10(-5) M (at 22 degrees C). The sodium-deoxycholate-insoluble proteins from the microsomal fraction also have Ca2+-binding components. The soluble Ca2+-binding protein has properties similar to and may be identical to Ca2+-binding proteins which have been isolated from bovine brain and have been demonstrated to be modulators of brain cyclic nucleotide phosphodiesterase and of actinomyosin ATPase. It also resembles Ca2+-binding proteins isolated from bovine adrenals and the electroplax from electrophorus electricus.
从牛神经垂体匀浆的可溶部分分离出一种酸性钙结合蛋白。该蛋白分子量为35000，亚基分子量为15000。纯化过程包括硫酸铵分级分离、DEAE - 纤维素层析以及在Sephadex G - 100和Sephadex G - 50上的凝胶过滤。常规和十二烷基硫酸钠 - 聚丙烯酰胺凝胶电泳表明它是一种不同于S - 100蛋白和神经垂体中丰富的可溶性激素结合蛋白（神经垂体素）的蛋白质。这似乎是匀浆可溶部分中唯一的Ca2 +结合蛋白，其对Ca2 +的表观解离常数Kdiss为1.1×10（-5）M（22℃时），每摩尔蛋白的钙结合能力为2摩尔。在牛神经垂体微粒体部分的脱氧胆酸钠可溶蛋白中分别鉴定出两种分子量为16500和68000的不同Ca2 +结合蛋白。其中一种（前者）已通过DEAE - 纤维素层析和Sephadex G - 200凝胶过滤以高纯度分离出来。该蛋白每摩尔蛋白结合4摩尔钙，表观解离常数Kdiss为1.0×10（-5）M（22℃时）。微粒体部分的脱氧胆酸钠不溶蛋白也有Ca2 +结合成分。可溶性Ca2 +结合蛋白具有与从牛脑分离出的Ca2 +结合蛋白相似的性质，并且可能相同，这些Ca2 +结合蛋白已被证明是脑环核苷酸磷酸二酯酶和肌动球蛋白ATP酶的调节剂。它也类似于从牛肾上腺和电鳗电板分离出的Ca2 +结合蛋白。
