Siddiqui A A, Sultana T, Buchholz N P, Waqar M A, Talati J
Department of Biochemistry, The Aga Khan University, Karachi, Pakistan.
Urol Res. 1998;26(6):383-8. doi: 10.1007/s002400050073.
Knowledge of the essential characteristics of macromolecules constituting the organic matrix of the nidus of urinary stones is required to understand the mechanism of urolithogenesis. The aim of this study was to isolate and characterise those stone nidus proteins. Using an extraction buffer containing SDS and beta-mercaptoethanol, we were able to overcome known problems of protein isolation from urinary stone matrix. These proteins were characterised by a strong tendency to aggregate under reducing and denaturing conditions. On SDS-PAGE, their molecular weights range from < or = 12 to 66 kDa. Antisera raised against stone matrix proteins showed a cross-reactivity between proteins isolated from different stones irrespective of their origin or mineral composition. Moreover, urinary proteins from stone formers also cross-reacted with these whereas there was no reaction with urinary proteins of non-stone formers. Western blotting confirmed these findings. Given the above summarised properties, it can be safely concluded that these proteins are prevalent in urines of stone formers, that they are selectively incorporated into renal stones of all aetiologies, and that they most likely have a role in nidus and, therefore, early stone formation.
为了理解尿石症的发病机制，需要了解构成尿结石核心有机基质的大分子的基本特征。本研究的目的是分离并鉴定那些结石核心蛋白。通过使用含有SDS和β-巯基乙醇的提取缓冲液，我们能够克服从尿结石基质中分离蛋白质时已知的问题。这些蛋白质的特点是在还原和变性条件下有强烈的聚集倾向。在SDS-PAGE上，它们的分子量范围从≤12 kDa到66 kDa。针对结石基质蛋白产生的抗血清显示，从不同结石中分离出的蛋白质之间存在交叉反应，无论其来源或矿物质成分如何。此外，结石形成者的尿液蛋白也与这些蛋白发生交叉反应，而非结石形成者的尿液蛋白则无反应。蛋白质印迹法证实了这些发现。鉴于上述总结的特性，可以有把握地得出结论，这些蛋白质在结石形成者的尿液中普遍存在，它们被选择性地纳入所有病因的肾结石中，并且它们很可能在结石核心形成以及早期结石形成中发挥作用。
