Abdulwajid A W, Sarkar B
Proc Natl Acad Sci U S A. 1983 Jul;80(14):4509-12. doi: 10.1073/pnas.80.14.4509.
Kidney is the target organ where nickel is accumulated and subsequently excreted in the urine after an intraperitoneal administration of 63NiCl2 in rats. The radioactive nickel is found mostly bound to a low molecular weight protein in kidney, which was isolated, purified, and partially characterized in this study. Homogeneity of this protein was determined by polyacrylamide gel electrophoresis. Amino acid analysis showed the presence of high amounts of glycine and proline and low amounts of phenylalanine, tyrosine, hydroxyproline, and hydroxylysine. The protein was found to be a glycoprotein with a carbohydrate content of 10% (wt/wt). Preliminary carbohydrate analysis showed that this glycoprotein is a high mannose-type containing mannose, galactose/glucose, and glucosamine. On the basis of the amino acid and carbohydrate analyses, the molecular weight of the glycoprotein is about 15,000-16,000. In vitro addition of nickel to the kidney cytosol also showed the presence of this protein. The protein appeared not to be affected or altered in its nickel-binding capacity by intraperitoneal or intravenous administration of actinomycin D, indicating it to be a noninducible protein. The glycoprotein demonstrated many characteristics of renal basement membrane. It is proposed that this protein is either a part of the renal basement membrane or is a part of the procollagen in the process of its conversion to collagen of the renal basement protein. The protein has a high affinity for nickel. It also may possess a similar binding affinity for other metals as well and may constitute a natural process of handling toxic levels of metals to be excreted.
肾脏是大鼠腹腔注射63NiCl2后镍蓄积并随后经尿液排出的靶器官。放射性镍主要与肾脏中的一种低分子量蛋白质结合，本研究对该蛋白质进行了分离、纯化和部分特性鉴定。通过聚丙烯酰胺凝胶电泳确定了该蛋白质的均一性。氨基酸分析表明，该蛋白质含有大量的甘氨酸和脯氨酸，而苯丙氨酸、酪氨酸、羟脯氨酸和羟赖氨酸的含量较低。该蛋白质是一种糖蛋白，碳水化合物含量为10%（重量/重量）。初步的碳水化合物分析表明，这种糖蛋白是一种高甘露糖型，含有甘露糖、半乳糖/葡萄糖和氨基葡萄糖。根据氨基酸和碳水化合物分析，该糖蛋白的分子量约为15,000-16,000。在肾脏细胞溶胶中体外添加镍也显示了这种蛋白质的存在。腹腔或静脉注射放线菌素D后，该蛋白质的镍结合能力似乎未受影响或改变，表明它是一种非诱导性蛋白质。该糖蛋白表现出许多肾基底膜的特征。有人提出，这种蛋白质要么是肾基底膜的一部分，要么是原胶原在转化为肾基底膜蛋白胶原过程中的一部分。该蛋白质对镍具有高亲和力。它对其他金属也可能具有类似的结合亲和力，并且可能构成处理待排泄金属毒性水平的自然过程。
