Heterogeneity of insulin-like growth factor-I affinity for the insulin-like growth factor-II receptor: comparison of natural, synthetic and recombinant DNA-derived insulin-like growth factor-I.
Heterogeneity of insulin-like growth factor-I affinity for the insulin-like growth factor-II receptor: comparison of natural, synthetic and recombinant DNA-derived insulin-like growth factor-I.
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胰岛素样生长因子-I 对胰岛素样生长因子-II 受体亲和力的异质性：天然、合成和重组 DNA 衍生的胰岛素样生长因子-I 的比较。
DOI：
10.1016/0006-291x(87)90650-4
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发表时间：
1987
影响因子：
3.1
通讯作者：
Li,CH
中科院分区：
文献类型：
--
作者：
Rosenfeld,RG;Conover,CA;Hodges,D;Lee,PD;Misra,P;Hintz,RL;Li,CH
虽然胰岛素样生长因子（IGF）I和II以高亲和力与结构上离散的受体结合，但它们以较低的亲和力与彼此的受体结合。我们已经评估了五种不同的IGF-I制剂（三种天然IGF-I制剂，一种合成制剂和一种重组DNA衍生物）对大鼠胎盘膜、18-54、SF细胞和BRL-3A细胞中IGF-II受体的亲和力。在测试的所有组织中，天然IGF-I制剂对IGF-II受体的亲和力是IGF-II的10-20%。然而，重组和合成IGF-I制剂对该受体的亲和力明显低于天然IGF-I，在肽浓度高达400 ng/ml时，（125-I）碘IGF-II结合仅降低10-25%。天然IGF-I制剂的放射免疫分析与针对独特的C-肽区域的IGF-II的抗体证明，污染的IGF-I制剂与免疫反应性IGF-II不能超过5%。这些结果表明，从人血浆中纯化的IGF-I与合成或重组IGF-I相比，对IGF-II受体具有不同的亲和力。此外，这些数据与IGF-I本身可能是异质性的假设一致，并且亚型对IGF受体的亲和力可能不同。或者，被认为是纯的IGF-I制剂可能被少量IGF-II污染，导致IGF-I对II型IGF受体的亲和力被高估。
Although insulin-like growth factors (IGF) I and II bind with high affinity to structurally discrete receptors, they bind with a lesser affinity to each other's receptor. We have evaluated the affinity of five different IGF-I preparations (three natural IGF-I preparations, one synthetic preparation, and one recombinant DNA-derived) for the IGF-II receptor in rat placental membranes, 18–54, SF cells and BRL-3A cells. In all tissues tested, the natural IGF-I preparations demonstrated an affinity for the IGF-II receptor which was 10–20% that of IGF-II. However, the recombinant and synthetic IGF-I preparations exhibited substantially lower affinities than natural IGF-I for this receptor, with only 10–25% reduction in (125-I)iodo IGF-II binding at peptide concentrations up to 400 ng/ml. Radioimmunoassay of the natural IGF-I preparations with an antibody directed against the unique C-peptide region of IGF-II demonstrated that contamination of IGF-I preparations with immunoreactive IGF-II could not exceed 5%. These results demonstrate that IGF-I purified from human plasma has a different affinity for the IGF-II receptor than does synthetic or recombinant IGF-I. Furthermore, there data are consistent with the hypothesis that IGF-I, itself, may be heterogeneous, and that subforms may vary in their affinities for the IGF receptors. Alternatively, IGF-I preparations which have been considered to be pure may be contaminated with small amounts of IGF-II, resulting in overestimation of the affinity of IGF-I for the type II IGF receptor.