Nakagawa Y, Renz C L, Ahmed M, Coe F L
Nephrology Program, University of Chicago, Illinois 60637.
Am J Physiol. 1991 Feb;260(2 Pt 2):F243-8. doi: 10.1152/ajprenal.1991.260.2.F243.
Nephrocalcin (NC), a urinary calcium oxalate monohydrate (COM) crystal growth inhibitor, was purified from kidneys of nine vertebrate species including humans. All isolates were glycoproteins with high contents of aspartic and glutamic acids and small amounts of basic and aromatic amino acids. Carbohydrate contents ranged from 4 to 16 wt% among the different species, but all contained fucose, mannose, galactose, glucose, galactosamine, glucosamine, and N-acetylneuraminic acid. Although amino acid and carbohydrate compositions were similar, dissociation constants derived from calcium oxalate monohydrate inhibition varied between 10(-7) and 10(-8) M, and highest affinity could be related to highest ability of the kidney of origin to concentrate urine. Using an antibody raised against NC from human kidney tissue culture medium, we found strong immunoreactivity with two species, pigs and sheep. Thus far all vertebrate kidneys possess COM growth-inhibiting material that seems to be of glycoprotein character, and all the glycoproteins isolated so far share similar features, suggesting NC-like proteins are a well-conserved trait.
肾钙素（NC）是一种草酸钙一水合物（COM）晶体生长抑制剂，从包括人类在内的9种脊椎动物的肾脏中纯化得到。所有分离物均为糖蛋白，天冬氨酸和谷氨酸含量高，碱性和芳香族氨基酸含量少。不同物种的碳水化合物含量在4%至16%（重量）之间，但均含有岩藻糖、甘露糖、半乳糖、葡萄糖、半乳糖胺、葡萄糖胺和N-乙酰神经氨酸。尽管氨基酸和碳水化合物组成相似，但一水合草酸钙抑制的解离常数在10^(-7)至10^(-8)M之间变化，最高亲和力可能与来源肾脏浓缩尿液的最高能力有关。使用针对人肾组织培养基中NC产生的抗体，我们发现猪和羊这两个物种有强烈的免疫反应性。迄今为止，所有脊椎动物的肾脏都拥有似乎具有糖蛋白特性的COM生长抑制物质，而且到目前为止分离出的所有糖蛋白都有相似特征，这表明类NC蛋白是一种保存良好的特性。
