Cornell H J
Prep Biochem. 1982;12(1):57-76. doi: 10.1080/00327488208065550.
Various procedures for the isolation of insulin-like growth factors (IGF's) from human plasma were evaluated with emphasis upon the yields of each species obtained. The procedures which were evaluated as first steps from plasma and mixed Cohn fractions included acid-ethanol extraction, heat coagulation, ion-exchange chromatography and gel filtration. Certain two-step combinations of these techniques were also evaluated in order to obtain higher fold-purification. Fractions obtained were tested initially using a competitive binding protein assay and then by radioimmunoassay (RIA) for IGF I and II. The results indicated that acceptable yields of IGF I and II were obtained by initial gel filtration of acidified plasma on Sephadex G-75 at pH 2.5 followed by chromatography on S.P. Sephadex C-25. Isoelectric focusing of the active fraction thereby obtained under these conditions and subsequent R.I.A. indicated total recoveries of IGF I and II of about 23 and 96 mU/litre respectively. Peak recoveries of IGF I were obtained in a fraction of pI 7.6-8.2 and IGF II between pI 5.9 and 6.9. The order in which the two steps of gel filtration and ion exchange chromatography were carried out appeared to alter the distribution of IGF's obtained. When ion exchange chromatography was used as the first step, most of the activity was obtained in fractions of pI 4.4-5.9 and was not immunoreactive IGF I or II.
对从人血浆中分离胰岛素样生长因子（IGF）的各种方法进行了评估，重点是每种物质的产量。作为从血浆和混合科恩组分开始的第一步所评估的方法包括酸乙醇提取、热凝固、离子交换色谱法和凝胶过滤。还评估了这些技术的某些两步组合，以获得更高倍数的纯化。最初使用竞争性结合蛋白测定法对获得的组分进行测试，然后通过放射免疫测定法（RIA）检测IGF I和II。结果表明，通过在pH 2.5条件下将酸化血浆在Sephadex G - 75上进行初步凝胶过滤，随后在S.P. Sephadex C - 25上进行色谱分离，可获得可接受的IGF I和II产量。在这些条件下对由此获得的活性组分进行等电聚焦，随后进行RIA，结果表明IGF I和II的总回收率分别约为23和96 mU/升。IGF I的峰值回收率出现在pI 7.6 - 8.2的组分中，IGF II的峰值回收率出现在pI 5.9和6.9之间。凝胶过滤和离子交换色谱两步法的实施顺序似乎会改变所获得的IGF的分布。当离子交换色谱法作为第一步时，大部分活性出现在pI 4.4 - 5.9的组分中，且不是免疫反应性的IGF I或II。
