Young D V, Nakano E T, Wiggins D S, McElaney M A
J Cell Physiol. 1978 Aug;96(2):147-53. doi: 10.1002/jcp.1040960203.
A serum factor which enhances the growth/viability of SV40 transformed 3T3 mouse fibroblasts, but not untransformed 3T3 cells in tissue culture has been partially purified from calf serum. The purification, which involves acidification to pH 2, chromatography on Sephadex G-100 at pH 2 followed by either Sephadex G-25 or BioGel P-2, results in material exhibiting two ninhydrin positive spots on thin layer chromatography and five to six dansylatable bands on SDS gels. This substance, termed Peak III or Serum Factor III, has been found in every serum examined thus far (including calf, rat, mouse, goat, lamb, rabbit, pig, horse, and chicken) and appears to be a low molecular weight, heat-insensitive molecule. Attempts to characterize it by chemical analyses and specific enzymatic inactivation have been either negative or inconclusive. Its biological mode of action is presently obscure. While it does not effect DNA synthesis, it does greatly increase the viability of SV3T3 cultures growing in low serum (0.15-0.30% calf serum) medium and, when added to "stationary phase" cells, restores healthy proliferation. This and evidence reported by others suggest that Peak III may affect SV3T3 cells in either overcoming a potentially lethal block in G1 or in passage through G2/M.
已从小牛血清中部分纯化出一种血清因子，该因子可增强SV40转化的3T3小鼠成纤维细胞在组织培养中的生长/活力，但对未转化的3T3细胞无此作用。纯化过程包括酸化至pH 2，在pH 2条件下于Sephadex G - 100上进行层析，随后用Sephadex G - 25或BioGel P - 2进行处理，得到的物质在薄层色谱上呈现两个茚三酮阳性斑点，在SDS凝胶上呈现五到六个可丹磺酰化的条带。这种物质被称为峰III或血清因子III，到目前为止在检测的每种血清中（包括小牛、大鼠、小鼠、山羊、羔羊、兔子、猪、马和鸡）均有发现，似乎是一种低分子量、对热不敏感的分子。通过化学分析和特异性酶失活对其进行表征的尝试要么得到阴性结果，要么尚无定论。其生物学作用模式目前尚不清楚。虽然它不影响DNA合成，但确实能极大地提高在低血清（0.15 - 0.30%小牛血清）培养基中生长的SV3T3培养物的活力，并且当添加到“静止期”细胞中时，可恢复健康的增殖。这以及其他人报道的证据表明，峰III可能通过克服G1期潜在的致死性阻滞或通过G2/M期来影响SV3T3细胞。
