CHARACTERIZATION OF CATIONIC ALBUMIN IN MINIMAL CHANGE NEPHROPATHY
CHARACTERIZATION OF CATIONIC ALBUMIN IN MINIMAL CHANGE NEPHROPATHY
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DOI：
10.1038/ki.1987.243
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发表时间：
1987-10-01
影响因子：
19.6
通讯作者：
GUSMANO, R
中科院分区：
文献类型：
--
作者：
GHIGGERI, GM;GINEVRI, F;GUSMANO, R
与正常蛋白相比，阴离子电荷较少的异白蛋白（pI = 4.7）的存在是微小病变肾病（MCN）中蛋白尿的标志。类固醇诱导的接近正常水平的蛋白尿恢复的特征是尿中出现的异白蛋白，其pI仍比正常的阴离子更强。在我们寻找pI变化的解释时，我们使用颗粒状凝胶中的制备等电聚焦将从9名MCN受影响的儿童获得的微不均匀条带分成4个部分（A1，A2，A3，A4），pI从5.8降低到4.0，我们确定了它们的脂肪酸含量。阴离子含量最低的组分A1是最脱脂的，其次是A2、A3和A4，其中脂肪酸含量逐渐增加，A4是最含脂的组分。因此，蛋白尿儿童尿白蛋白中脂肪酸的平均含量低于缓解期和正常儿童（2.17 ± 0.05）。0.03与20.91 . ±. 0.38和20.94 . ±. 0.39），并且与疾病的相同阶段中的血清白蛋白相比低4倍（2.17 ± 0.39）。0.03与8.59 .+-相比。1.64）。在中链和长链脂肪酸中，血清和尿白蛋白之间的比率对于亚油酸最高（约7），其次是油酸、棕榈酸和月桂酸。在其他5例非MCN肾病综合征患者中，几乎所有FA的这一比值约为1。这些数据表明，在MCN蛋白尿中，尿白蛋白的等电点是其脂肪酸含量的函数，并且尿中仅存在部分脱脂的异白蛋白（尤其是具有痕量亚油酸的那些）。他们进一步表明，脂肪酸不能与阳离子异白蛋白反应是由于与一种（或多种）不带电荷、仍未表征的物质的竞争机制或蛋白质的含脂肪酸口袋的不可接近性造成的。
The presence of isoalbumins with a less anionic charge than the normal protein (pI = 4.7) is the hallmark of proteinuria in minimal change nephropathy (MCN). Steroid-induced restoration of near normal levels of proteinuria is characterized by the appearance in urines of isoalbumins with a pI still more anionic than the normal. In our search for an explanation for the pI changes, we used preparative isoelectric focusing in granulated gels to split the microheterogeneous bands obtained from nine MCN-affected children into four fractions (A1, A2, A3, A4) with decreasing pI from 5.8 to 4.0 and we have determined their fatty acid content. The least anionic fraction, A1, was the most defatted, followed by A2, A3 and A4 in which fatty acid content progressively increased, A4 being the most fatted fraction. Accordingly, the mean content of fatty acids in urinary albumin in proteinuric children was lower than in both the remission phase and in normal children (2.17 .+-. 0.03 vs. 20.91 .+-. 0.38 and 20.94 .+-. 0.39, respectively) and was lower by a factor of 4 compared to serum albumin in the same phase of the disease (2.17 .+-. 0.03 vs. 8.59 .+-. 1.64). Among medium and long-chain fatty acids, the ratio between serum and urinary albumin was the highest for linoleic acid (.apprx.7), followed by that of oleic acid, palmitic acid and lauric acid. At variance in five other patients affected by non-MCN nephrotic syndrome this ratio was for practically all FAs about 1. These data indicate that in MCN proteinuria the isoelectric point of urinary albumin is a function of its fatty acid content and that only partially defatted isoalbumins (especially those with trace amount of linoleic acid) are present in urines. They further suggest that the inability of fatty acids to react with cationic isoalbumins is brought about by competitive mechanisms with one (or more) uncharged, still uncharacterized substance(s) or an inaccessibility of the fatty acid-containing pocket of the protein.