Lehmann W, Samtleben R, Graetz H, Langen P
Eur J Cancer Clin Oncol. 1983 Jan;19(1):101-7. doi: 10.1016/0277-5379(83)90404-2.
A factor which inhibits the resumption of proliferation of stationary Ehrlich ascites mammary carcinoma (EAC) cells in vitro was isolated from the normal, lactating bovine mammary gland. After fractionation of the 50,000 g supernatant of the tissue homogenate by ammonium sulfate precipitation and gel filtration, it was further purified 2600-fold by ultrafiltration and lectin affinity chromatography. Polyacrylamide electrophoresis revealed one band containing all the activity. SDS gel electrophoresis showed a main band corresponding to a protein with a molecular weight of about 15,000 dalton. At this state of purity the factor concentration for half-maximal inhibition of proliferation was 12 ng/ml or 8 X 10(-10) M. The effects of factor concentrations of 4 X 10(-9) or 4 X 10(-8) M are abolished by 5 X 10(-9) M insulin almost completely or to 70%.
从正常泌乳期牛乳腺中分离出一种能够抑制静止期艾氏腹水乳腺癌（EAC）细胞在体外恢复增殖的因子。将组织匀浆50,000g上清液经硫酸铵沉淀和凝胶过滤分级分离后，再通过超滤和凝集素亲和层析进一步纯化2600倍。聚丙烯酰胺电泳显示一条含有所有活性的条带。SDS凝胶电泳显示一条主带，对应分子量约为15,000道尔顿的一种蛋白质。在这种纯度状态下，抑制增殖达到半数最大效应时的因子浓度为12ng/ml或8×10⁻¹⁰M。4×10⁻⁹或4×10⁻⁸M的因子浓度的作用几乎被5×10⁻⁹M胰岛素完全消除或消除70%。
