Worcester E M, Nakagawa Y, Wabner C L, Kumar S, Coe F L
Renal Program, Pritzker School of Medicine, University of Chicago, Illinois 60637.
Am J Physiol. 1988 Dec;255(6 Pt 2):F1197-205. doi: 10.1152/ajprenal.1988.255.6.F1197.
Urine inhibition of calcium oxalate monohydrate (COM) crystal growth (CG) seems due to a glycoprotein that contains gamma-carboxyglutamic acid and has been named nephrocalcin (NC); however, Tamm-Horsfall protein (THP) and albumin resemble NC and make its measurement and role uncertain. NC in urine is aggregated to molecular mass 64 kDa and higher, similar to albumin (64 kDa) and THP (87 kDa). Albumin and THP are calcium binding, albumin adsorbs to COM crystals, and THP has been described as an inhibitor of COM growth. Antisera to NC have cross-reacted with THP even though the NC was isolated from cultured renal cells. Here we have compared highly purified NC, THP, and albumin adsorption with COM crystals and CG inhibition; also we compared their patterns of cross-reactivities with a new antiserum against NC and a monoclonal antibody to THP. NC adsorbs to COM crystals, THP does not. Albumin and THP do not inhibit CG. Cross-reactivity of albumin and THP to the antiserum is slight by direct enzyme-linked immunosorbent assay and nonexistent by competitive ELISA; reaction of NC to the anti-THP monoclonal antibody is absent.
尿液对一水合草酸钙（COM）晶体生长（CG）的抑制作用似乎归因于一种含有γ-羧基谷氨酸的糖蛋白，该蛋白被命名为肾钙素（NC）；然而，Tamm-Horsfall蛋白（THP）和白蛋白与NC相似，这使得对NC的测量及其作用变得不确定。尿液中的NC聚集形成分子量为64 kDa及以上的物质，类似于白蛋白（64 kDa）和THP（87 kDa）。白蛋白和THP都能结合钙，白蛋白可吸附到COM晶体上，并且THP被描述为COM生长的抑制剂。尽管NC是从培养的肾细胞中分离出来的，但针对NC的抗血清仍与THP发生交叉反应。在此，我们比较了高度纯化的NC、THP和白蛋白对COM晶体的吸附作用以及对晶体生长的抑制作用；此外，我们还比较了它们与一种针对NC的新抗血清和一种针对THP的单克隆抗体的交叉反应模式。NC可吸附到COM晶体上，而THP则不能。白蛋白和THP不会抑制晶体生长。通过直接酶联免疫吸附测定，白蛋白和THP与抗血清的交叉反应很轻微，而通过竞争性ELISA则不存在交叉反应；NC与抗THP单克隆抗体没有反应。
