Miyazaki T, Hachiya T, Kajita Y, Ochi Y, Fujiyama Y, Hosoda S
Clin Chim Acta. 1982 Jul 1;122(2):161-8. doi: 10.1016/0009-8981(82)90275-3.
We have recently suggested that carcinoembryonic antigen (CEA) may contain alpha 1-acid glycoprotein (AG) antigenic determinant. In the present work we examined a protein with CEA-like activity in the feces of healthy subjects (NCA) for immunological cross-reactivity with AG. When the perchloric acid extract of feces was fractionated on a Sephadex G-200, two fractions (large and small molecular weight) were obtained. The large molecular weight fraction had higher CEA activity than the small one. The perchloric acid (PCA) extract of feces was subjected to affinity chromatography using anti-CEA bound to Sepharose, and the bound protein was labelled with 125I, and then fractionated on a Sephadex G-200 column. Two radioactive peaks, Peak 1 corresponding to an approximate Mr of 180 000 and Peak 2, corresponding to an approximate Mr of 60 000 were found. Both peaks showed immunoreactivity with either anti-CEA or anti-AG. This experiment suggests the presence of two kinds of CEA-reactive proteins in feces: one which may be a big protein with immunological similarity to AG and a second which appears to be a hydrolysed fragment of this protein.
我们最近提出癌胚抗原（CEA）可能含有α1-酸性糖蛋白（AG）的抗原决定簇。在本研究中，我们检测了健康受试者粪便中具有CEA样活性的一种蛋白质（NCA）与AG的免疫交叉反应性。当粪便的高氯酸提取物在Sephadex G-200上进行分级分离时，得到了两个级分（大分子和小分子质量）。大分子质量级分的CEA活性高于小分子质量级分。粪便的高氯酸（PCA）提取物用结合到琼脂糖上的抗CEA进行亲和层析，结合的蛋白质用125I标记，然后在Sephadex G-200柱上进行分级分离。发现了两个放射性峰，峰1对应的近似相对分子质量为180 000，峰2对应的近似相对分子质量为60 千。两个峰均与抗CEA或抗AG表现出免疫反应性。该实验表明粪便中存在两种与CEA反应的蛋白质：一种可能是与AG具有免疫相似性的大蛋白质，另一种似乎是该蛋白质的水解片段。
