Staprans I, Garon S J, Hopper J, Felts J M
Biochim Biophys Acta. 1981 Dec 18;678(3):414-22. doi: 10.1016/0304-4165(81)90123-9.
Previously we found that alpha 2-acid glycoprotein fraction from urine of patients with the nephrotic syndrome stimulated the lipoprotein lipase reaction in vivo and in vitro. The activator was separated from the alpha 1-acid glycoprotein and identified as a glycosaminoglycan. The studies reported here were undertaken to characterize and quantify the glycosaminoglycans contained in urine of patients with the nephrotic syndrome and to compare these to the glycosaminoglycans in urine of the control subjects. We found that free low molecular weight glycosaminoglycans, heparan sulfate and chondroitin 4-sulfate, are excreted in both patients with the nephrotic syndrome and controls however, patients with the nephrotic syndrome excreted much less of both glycosaminoglycans. The free form of heparan sulfate was found to be the activator which stimulated the lipoprotein lipase reaction in vitro in the presence of apolipoprotein CII. In addition, the urine from patients with the nephrotic syndrome contained a protein-glycosaminoglycan complex which was absent in control urine. Glycosaminoglycans in the complex could be released by papain digestion or by trichloroacetic acid. Our evidence indicates that this glycosaminoglycans fraction is a law charge form of chondroitin sulfate.
此前我们发现，肾病综合征患者尿液中的α2-酸性糖蛋白组分在体内和体外均能刺激脂蛋白脂肪酶反应。该激活剂已从α1-酸性糖蛋白中分离出来，并被鉴定为一种糖胺聚糖。本文所报告的研究旨在对肾病综合征患者尿液中所含的糖胺聚糖进行表征和定量，并将其与对照受试者尿液中的糖胺聚糖进行比较。我们发现，游离的低分子量糖胺聚糖，即硫酸乙酰肝素和硫酸软骨素4-硫酸酯，在肾病综合征患者和对照者的尿液中均有排泄，然而，肾病综合征患者排泄的这两种糖胺聚糖都要少得多。硫酸乙酰肝素的游离形式被发现是在载脂蛋白CII存在的情况下在体外刺激脂蛋白脂肪酶反应的激活剂。此外，肾病综合征患者的尿液中含有一种蛋白-糖胺聚糖复合物，而对照尿液中则没有。复合物中的糖胺聚糖可通过木瓜蛋白酶消化或三氯乙酸释放出来。我们的证据表明，这种糖胺聚糖组分是硫酸软骨素的一种低电荷形式。
