Yamaoka K, Hirai R, Tsugita A, Mitsui H
J Cell Physiol. 1984 Jun;119(3):307-14. doi: 10.1002/jcp.1041190308.
A new class of transforming growth factor (TGF), with chemical characteristics differing from previously reported TGFs, was isolated and purified from an avian sarcoma virus-transformed rat cell line, 77N1 . Purification steps were simple and consisted of ion-exchange chromatography on diethylaminoethyl (DEAE)-Sephacel, ammonium sulfate precipitation, Chromatofocusing, and DEAE-Sephadex A-25 chromatography. The purified TGF is a heat- and acid-labile protein with a molecular mass of 12,000 daltons and isoelectric point of 5.2-5.4. Because of the acid lability of this TGF, purification was carried out at neutral pH. The TGF induced DNA synthesis in growth-arrested BALB 3T3 cells and promoted anchorage-independent growth of nontransformed BALB 3T3 cells in soft agar; the latter activity is specific for the peptide growth factors, called TGFs, but it did not compete with epidermal growth factor (EGF) for binding to the EGF membrane receptors. The TGF activity was not potentiated by EGF. The purified preparation of the TGF stimulated BALB 3T3 cells to grow progressively in soft agar at a dose of 20 ng/ml.
从禽肉瘤病毒转化的大鼠细胞系77N1中分离并纯化出一类新的转化生长因子（TGF），其化学特性与先前报道的TGF不同。纯化步骤简单，包括在二乙氨基乙基（DEAE）-Sephacel上进行离子交换色谱、硫酸铵沉淀、聚焦色谱和DEAE-Sephadex A-25色谱。纯化后的TGF是一种对热和酸不稳定的蛋白质，分子量为12,000道尔顿，等电点为5.2 - 5.4。由于这种TGF对酸不稳定，因此在中性pH下进行纯化。该TGF可诱导生长停滞的BALB 3T3细胞中的DNA合成，并促进未转化的BALB 3T3细胞在软琼脂中进行不依赖贴壁的生长；后一种活性是被称为TGF的肽生长因子所特有的，但它不能与表皮生长因子（EGF）竞争结合EGF膜受体。EGF不能增强TGF的活性。纯化后的TGF制剂以20 ng/ml的剂量刺激BALB 软琼脂中的3T3细胞逐渐生长。
