Sato M, Schilsky M L, Stockert R J, Morell A G, Sternlieb I
Department of Medicine, Albert Einstein College of Medicine, Bronx, New York 10461.
J Biol Chem. 1990 Feb 15;265(5):2533-7.
Three polypeptides with apparent Mr = 200,000, 135,000, and 115,000, reacting with antibody to human ceruloplasmin (Cp), were consistently found in sera of normal adult and newborn subjects, patients with Wilson's disease, as well as in the oxidase-active fraction of purified human Cp, resolved by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The concentrations of the three Cp polypeptides were proportional to the total Cp oxidase activity measured in whole serum. Peptide mapping revealed that the three Cp polypeptides were closely related. Cross-linking of Cp135 resulted in dimers with electrophoretic mobility similar to that of Cp200. A common shift in electrophoretic mobility following N-glycanase treatment indicated that all three polypeptides were N-glycosylated, and that the apparent differences in molecular mass could not be related to the carbohydrate moiety. Immunoprecipitates of cell lysates of [35S]cysteine labeled HepG2 cells revealed the presence of two species of newly synthesized Cp polypeptides, Mr 200,000 and 135,000, which were secreted into the media. Secretion of Cp200 by the human liver appears to be physiologic and may be the result of posttranslational modification of Cp135.
通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳分离，在正常成人和新生儿、威尔逊病患者的血清以及纯化的人铜蓝蛋白（Cp）的氧化酶活性部分中，始终发现三种表观分子量分别为200,000、135,000和115,000的多肽，它们能与人铜蓝蛋白抗体发生反应。这三种铜蓝蛋白多肽的浓度与全血清中测得的总铜蓝蛋白氧化酶活性成正比。肽图分析表明这三种铜蓝蛋白多肽密切相关。Cp135交联形成的二聚体电泳迁移率与Cp200相似。N-糖苷酶处理后电泳迁移率的共同变化表明，所有三种多肽都进行了N-糖基化，且表观分子量的差异与碳水化合物部分无关。[35S]半胱氨酸标记的HepG2细胞裂解物的免疫沉淀物显示存在两种新合成的铜蓝蛋白多肽，分子量分别为200,000和135,000，它们被分泌到培养基中。人肝脏分泌Cp200似乎是生理性的，可能是Cp135翻译后修饰的结果。
