Saito Y, Yasuhara M, Okumura K, Hori R
Biochem Pharmacol. 1985 Oct 1;34(19):3543-6. doi: 10.1016/0006-2952(85)90731-2.
The major serum binding protein of salmon calcitonin (sCT) in the rat was identified. High-molecular-weight (HMW) forms of sCT, produced by the incubation of radioactive sCT in rat serum, were isolated by gel filtration and analysed by chromatofocusing. The major radioactive peak was eluted at the region of albumin in gel filtration, and this peak had a slightly higher pI than albumin on chromatofocusing. Immunoreactivity of the radioactive peak fraction in chromatofocusing, examined by immunodiffusion, showed that the major protein in the fraction was albumin. Immunoreactivity of the radioactive HMW fraction isolated by gel filtration was studied by immunoprecipitation, indicating that a large portion of the fraction reacted with anti-rat albumin antiserum. These results suggested that the radioactive peak in chromatofocusing represents the complex of sCT and rat albumin. Further, HMW forms of sCT were analysed by immunoelectrophoresis and autoradiography, and most of the radioactivity was found on the precipitation line of albumin. These results demonstrate that the major binding protein of sCT in rat serum is albumin.
鉴定了大鼠体内鲑鱼降钙素（sCT）的主要血清结合蛋白。通过凝胶过滤分离并经层析聚焦分析了放射性sCT与大鼠血清孵育产生的高分子量（HMW）形式的sCT。在凝胶过滤中，主要放射性峰在白蛋白区域洗脱，且该峰在层析聚焦时的pI略高于白蛋白。通过免疫扩散检测层析聚焦中放射性峰级分的免疫反应性，结果表明该级分中的主要蛋白质是白蛋白。通过免疫沉淀研究凝胶过滤分离的放射性HMW级分的免疫反应性，结果表明该级分的大部分与抗大鼠白蛋白抗血清发生反应。这些结果提示，层析聚焦中的放射性峰代表sCT与大鼠白蛋白的复合物。此外，通过免疫电泳和放射自显影分析HMW形式的sCT，发现大部分放射性位于白蛋白的沉淀线上。这些结果证明，大鼠血清中sCT的主要结合蛋白是白蛋白。
