凝集素亲和层析研究人血清肝型碱性磷酸酶的糖链结构

用麦胚凝集素(WGA)将人血清肝型和骨型碱性磷酸酶(ALP)分离,再将肝型ALP通过蔓陀萝凝集素(DSA)亲和层析柱作醋酸梯度洗脱,发现正常人、急性肝炎、慢性肝炎、肝硬化和原发性肝癌各组各自的混合血清ALP的层析行为有明显差异。正常人只有不结合组分,而各种良性肝病出现数目不同(2—3个)的弱结合组分,肝癌则还出现3个強结合组分,各组分ALP在不同肝病血清中的出峰时间基本恒定。这种ALP洗脱峰的不均一性在单个病人血清中依然存在,是ALP糖链结构不同而引起的。由此推测肝病时ALP上N糖链的天线数增加,肝病越发展成慢性或恶性,血清ALP和DSA的亲和力也越強。这些结果有可能在临床上鉴别各类不同的肝病。

Studies on the Sugar Chain Structure of Alkaline Phosphatase in Human Sera Using Lectin Affinity Chromatography

The liver type alkaline phosphatase(ALP) was separated from bone type ALP by WGA lectin and chromatographied on DSA leotin affinity column using gradient elutlon with acetic acid. It was found that the ALP in the separately mixed sera from different groups of normal persons, patients of acute or chronic hepatitis, hepatocirrhosis and primary hepatocarcinoma showed significantly different chromatographic behavior on DSA column. In normal sera only the nonbinding fraction was present, whereas 2 to 3 weakly binding fractions were present in benign liver diseases and 3 strongly binding fractions in hepatocarcinoma. The elution time of various peaks were compatible respectively in different serum groups. This heterogeneity of elution peaks of ALP was also found in individual patients of hepatocarcinoma. The reason of the heterogeneity was proved to be the structural variation of sugar chain on ALP molecules, and it was suggested that the antenna of N-linked sugar chain was changed in the seral ALP of liver diseases. It was found that the more progressive the liver disease toward chronic or malignant stage, the stronger the binding of seral ALP sugar chain to DSA. These results may be applicable to differentiate different liver diseases.