Detection of larger polypeptides structurally and functionally related to type I transforming growth factor.
Detection of larger polypeptides structurally and functionally related to type I transforming growth factor.
复制标题
检测结构和功能上与 I 型转化生长因子相关的较大多肽。
DOI：
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发表时间：
1985
影响因子：
11.1
通讯作者：
G. Todaro
中科院分区：
文献类型：
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作者：
P. Linsley;W. R. Hargreaves;D. Twardzik;G. Todaro
利用化学方法合成了I型大鼠转化生长因子（rTGF）各区域对应的多肽，并将其偶联到载体蛋白上，用于免疫家兔。针对rTGF的羧基末端17个氨基酸对应的其中一种肽的抗血清已被用于开发具有竞争性的免疫肽RIA。在该实验中，抗血清仅与rTGF分子的11个羧基末端氨基酸对应的免疫肽的有限区域发生反应。完整的rTGF在摩尔基础上与免疫肽竞争，表明rTGF中的同源序列被该抗血清识别。小鼠表皮生长因子（mEGF）作为竞争对手是无效的，即使在10000倍的浓度下也是如此，这表明RIA能够将TGF与功能相关蛋白区分开来。通过条件培养基凝胶过滤，从培养的逆转录病毒转化大鼠细胞中检测到几种免疫反应性物质；在EGF放射受体试验中，低分子量的rTGF和高分子量的物种都具有生物活性。免疫印迹分析高分子量峰组分显示有三种多肽（MrS、24000、40000和42000）与抗血清特异性反应。这些发现表明存在一个包含rTGF结构和功能决定因素的较大多肽家族。
Peptides corresponding to various regions of type I rat transforming growth factor (rTGF) have been chemically synthesized, conjugated to carrier protein, and used to immunized rabbits. An antiserum raised against one of these peptides, corresponding to the carboxyl-terminal 17 amino acids of rTGF, has been used to develop a competitive RIA for the immunizing peptide. In this assay, the antiserum reacts only with a restricted region of the immunizing peptide corresponding to the 11 carboxyl-terminal amino acids of the rTGF molecule. Intact rTGF competes as well as the immunizing peptide on a molar basis, indicating that the cognate sequence in rTGF is recognized by this antiserum. Mouse epidermal growth factor (mEGF) was ineffective as a competitor, even at a 10,000-fold greater concentration, showing that the RIA was capable of distinguishing TGF from functionally related proteins. Several immunoreactive species were detected by gel filtration of conditioned medium from cultured retrovirus-transformed rat cells; both a low molecular weight species that corresponds to rTGF, and a higher molecular weight specie(s) copurify with biologic activity in the EGF radioreceptor assay. Immunoblotting analysis of the higher molecular weight peak fractions revealed three polypeptides (MrS, 24,000, 40,000, and 42,000) that reacted specifically with the antiserum. These findings suggest the existence of a family of larger polypeptides containing both structural and functional determinants of rTGF.