Graham G J, Freshney M G, Donaldson D, Pragnell I B
CRC Beatson Laboratories, Beatson Institute for Cancer Research, Bearsden, Glasgow.
Growth Factors. 1992;7(2):151-60. doi: 10.3109/08977199209046404.
We have recently characterised an inhibitor of haemopoietic stem cell proliferation (SCI/MIP-1 alpha) and report here on its purification and initial biological and biochemical characterisation. The activity can be detected by direct addition to the CFU-A stem cell assay and this simple test for inhibitory activity has greatly facilitated the purification of the molecule. The purification involves a combination of Mono Q ion exchange chromatography, heparin-sepharose affinity chromatography and Blue Sepharose affinity chromatography. The purified stem cell inhibitor is an 8 kD peptide which is identical to the previously described peptide macrophage inflammatory protein 1 alpha. The peptide has a natural tendency to form large self-aggregates and appears, in physiological buffers, to have a native molecular weight of around 90 kD. SCI is a heat stable, protease sensitive protein which is half maximally active at between 10 and 25 pM in the CFU-A assay. The self-aggregates can be disrupted by dilute solutions of acetic acid and it appears that disruption increases the specific activity of SCI preparations. We also report the characterisation of the human homologue of the stem cell inhibitor (human SCI/MIP-1 alpha) which is 74% identical to murine MIP-1 alpha and which shares all the above features of the murine inhibitor.
我们最近鉴定了一种造血干细胞增殖抑制剂（SCI/MIP-1α），在此报告其纯化以及初步的生物学和生化特性。通过直接添加到CFU-A干细胞测定中可检测到该活性，这种抑制活性的简单测试极大地促进了该分子的纯化。纯化过程包括Mono Q离子交换色谱、肝素-琼脂糖亲和色谱和蓝色琼脂糖亲和色谱的组合。纯化的干细胞抑制剂是一种8 kD的肽，与先前描述的肽巨噬细胞炎性蛋白1α相同。该肽具有形成大的自我聚集体的天然倾向，在生理缓冲液中，其天然分子量约为90 kD。SCI是一种热稳定、对蛋白酶敏感的蛋白质，在CFU-A测定中，其在10至25 pM之间时活性达到最大值的一半。自我聚集体可被稀乙酸溶液破坏，并且破坏似乎增加了SCI制剂的比活性。我们还报告了干细胞抑制剂的人类同源物（人类SCI/MIP-1α）的特性，它与小鼠MIP-1α有74%的同一性，并且具有小鼠抑制剂的所有上述特征。
