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Studies on human osteopontin : isolation and characterization of osteopontin in milk and serum.

人骨桥蛋白的研究：牛奶和血清中骨桥蛋白的分离和表征。

基本信息

批准号：
09557062
负责人：
KOBAYASHI Kunihiko
金额：
$ 5.89万
依托单位：
HOKKAIDO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09557062/
关键词：
osteopontin Ca-binding human milk human serum molecular fragility Ca結合蛋白母乳血清

项目摘要

Osteopontin (hereafter called as OPN), a CaィイD12+ィエD1 binding protein, has been studied as a secreted highly acidic phophoglycoprotein with diverse functions in various tissue and species. It was firstly isolated from mineralized bone matrix and studied as a protein remodeling mineralized tissue. Since OPN is present in human milk, we considered that the OPN plays an important role in the osteogenesis in the developing infants. The present studies aimed to isolate and characterize OPN in human milk, serum and blood cells.We have isolated osteopontin from human milk, prepared antibodies specific for it, and tried to establish a sandwich type EIA system determining osteopontin in serum. It was found that serum osteopontin but not milk osteopontin showed paradoxical phenomena in reaction with the antibodies, making no detectable precipitation in immunoelectrophoresis and no positive reaction in EIA, but showing positive reaction in Western blot and in an inhibition tests. Taking these phenomena and other circumstantial evidences into account, it is concluded that the serum osteopontin has a high molecular fragility, fragmenting into small peptides with few epitopes during incubation time. This fragility, though much lower extent, was also seen in milk osteopontin. Although the exact casual meaning of this fragility was not defined yet, it is conceivable that the fragility of OPN itself has some meaning in its physiological functions. Such possibility is being investigated in our laboratory.

骨桥蛋白(OPn)是一种钙结合蛋白(CaィイD12+ィエD1)，是一种分泌型高酸性磷酸糖蛋白，在多种组织和物种中具有不同的功能。它最初是从矿化骨基质中分离出来的，作为一种蛋白质重塑矿化组织进行了研究。由于OPN存在于母乳中，我们认为OPN在发育中的婴儿的成骨过程中起着重要作用。本研究旨在从母乳、血清和血细胞中分离和鉴定骨桥蛋白，从母乳中分离骨桥蛋白，制备其特异性抗体，并尝试建立夹心式EIA检测血清骨桥蛋白的体系。结果表明，血清骨桥蛋白与抗体反应呈反常现象，免疫电泳法无明显沉淀，EIA无阳性反应，免疫印迹和抑制试验均呈阳性反应。考虑到这些现象和其他环境证据，我们认为血清骨桥蛋白具有很高的分子脆性，在孵育过程中会碎裂成几个小肽，表位很少。这种脆弱性虽然程度要小得多，但在牛奶骨桥蛋白中也能看到。虽然这种脆弱性的确切随意含义尚未定义，但可以想象，OPN本身的脆弱性在其生理功能中具有一定的意义。这种可能性正在我们的实验室中进行研究。