Pircher R, Jullien P, Lawrence D A
Biochem Biophys Res Commun. 1986 Apr 14;136(1):30-7. doi: 10.1016/0006-291x(86)90872-7.
Human blood platelets, the richest known source of beta-transforming Growth Factor extractable under acid conditions, release in neutral extracts (pH 7.2) a latent form of this growth factor with an apparent molecular weight of 400 Kd. This latent form, poorly active on rat NRK-49F indicator cells in soft agar assays can be activated by exposure to acid pH or 8 molar urea. The acid activated beta-Transforming Growth Factor from neutral extracts elutes on Biogel P60, in 1 molar acetic acid, as a broad peak of apparent molecular weight 15-30 Kd, like when this factor is extracted from platelets by the usual acid-ethanol procedure. Moreover, beta-Transforming Growth Factor from both acid activated neutral extracts and from acid-ethanol extracts elutes on reverse phase at 30% acetonitrile. We suggest that beta-Transforming Growth Factor is stored in human blood platelets as a poorly active high molecular weight complex which may be dissociated and activated in appropriate in vivo microenvironments.
人血小板是已知在酸性条件下可提取的β转化生长因子最丰富的来源，在中性提取物（pH 7.2）中释放出这种生长因子的一种潜在形式，其表观分子量为400 Kd。这种潜在形式在软琼脂试验中对大鼠NRK - 49F指示细胞的活性较差，可通过暴露于酸性pH值或8摩尔尿素来激活。从中性提取物经酸激活的β转化生长因子在1摩尔乙酸中于Biogel P60上洗脱，呈现表观分子量为15 - 30 Kd的宽峰，这与通过常规酸 - 乙醇法从血小板中提取该因子时的情况相同。此外，来自酸激活的中性提取物和酸 - 乙醇提取物的β转化生长因子在30%乙腈的反相条件下洗脱。我们认为β转化生长因子在人血小板中以活性较差的高分子量复合物形式储存，该复合物可能在适当的体内微环境中解离并被激活。
