Atmani F, Khan S R
Université Mohamed 1er, Faculté des Sciences, Département de Biologie, Oujda-Morocco.
Urol Res. 1999;27(1):57-61. doi: 10.1007/s002400050089.
Urine contains several macromolecules that inhibit calcium oxalate (CaOx) crystallization. Among them is bikunin, the light chain of most of the inter-alpha-inhibitor (IalphaI) family of glycoproteins. This study aimed to verify whether bikunin and other members of the IalphaI family are synthesized in the kidneys or derived exclusively from the plasma. Proteins extracted from homogenized bovine kidney were applied successively to three chromatographic steps on DEAE-Sephacel, Sephacryl S-300, and Mono Q column. The inhibitory activity was assayed using a CaOx crystallization system. The presence of IalphaI-related proteins was determined by electrophoresis and Western blotting. The results showed that kidney extract contained a 125-kDa protein that cross-reacted with anti-IalphaI antibodies. This protein inhibited CaOx crystallization efficiently. According to its molecular weight and immunoreaction with anti-IalphaI antibody, the 125-kDa protein could be pre-alpha-inhibitor. The latter is known to encompass a heavy chain and bikunin, which may explain its inhibitory activity against CaOx crystallization. Consequently, we hypothesize that kidneys may produce some IalphaI-related proteins that are involved in the inhibition of stone formation.
尿液中含有多种抑制草酸钙（CaOx）结晶的大分子物质。其中包括比库宁，它是大多数α-抑制因子（IαI）糖蛋白家族的轻链。本研究旨在验证比库宁和IαI家族的其他成员是在肾脏中合成的，还是仅来源于血浆。从匀浆牛肾中提取的蛋白质先后应用于DEAE-葡聚糖凝胶、Sephacryl S-300和Mono Q柱的三个色谱步骤。使用CaOx结晶系统测定抑制活性。通过电泳和蛋白质印迹法确定IαI相关蛋白的存在。结果表明，肾脏提取物中含有一种与抗IαI抗体发生交叉反应的125 kDa蛋白。该蛋白能有效抑制CaOx结晶。根据其分子量和与抗IαI抗体的免疫反应，125 kDa蛋白可能是前α-抑制因子。已知后者包含一条重链和比库宁，这可能解释了其对CaOx结晶的抑制活性。因此，我们推测肾脏可能产生一些与IαI相关的蛋白，这些蛋白参与了结石形成的抑制过程。
