Scott C D, Baxter R C
Endocrinology. 1987 Jan;120(1):1-9. doi: 10.1210/endo-120-1-1.
Rat liver microsomal insulin-like growth factor-II (IGF-II) receptor has been purified to homogeneity using a single step affinity chromatographic procedure on agarose-IGF-II with elution at pH 4. Determined by either IGF-II binding or a direct RIA for receptor, purification of 2000-fold was obtained. The mean recovery was 28% for five such preparations. Sodium dodecyl sulfate-electrophoresis and autoradiography of purified receptor, radioiodinated receptor, and affinity-labeled receptor all indicated a molecular mass of approximately 250K. Scatchard analysis of IGF-II binding to purified receptor, solubilized microsomal membranes, or plasma membranes showed a single class of binding site with an affinity constant of 6 X 10(10) liter/mol in all cases. Potent antibodies to the purified receptor were raised in rabbits, capable of inhibiting 50% of IGF-II binding at dilutions of 1:170,000 and also of fully precipitating IGF-II-prelabeled receptor at 1:50,000. Both types of antibodies reacted with IGF-II receptors in rat adipose tissue, brain, heart, kidney, lung, and spleen. However, little cross-reactivity was seen with other species. Comparison of the ability of receptor antibodies to inhibit IGF-II binding to microsomal and plasma membranes indicated a specific immunological difference between the IGF-II receptors in the two membrane preparations.
利用琼脂糖-胰岛素样生长因子-II（IGF-II）通过一步亲和色谱法，在pH 4条件下洗脱，已将大鼠肝脏微粒体胰岛素样生长因子-II（IGF-II）受体纯化至同质状态。通过IGF-II结合或受体直接放射免疫分析（RIA）测定，获得了2000倍的纯化倍数。对于五次这样的制备，平均回收率为28%。纯化受体、放射性碘化受体和亲和标记受体的十二烷基硫酸钠电泳及放射自显影均表明分子量约为250K。对纯化受体、溶解的微粒体膜或质膜进行的IGF-II结合的Scatchard分析表明，在所有情况下均存在一类结合位点，亲和常数为6×10¹⁰升/摩尔。用纯化受体在兔体内制备了高效抗体，该抗体在1:170,000稀释度下能够抑制50%的IGF-II结合，并且在1:50,000时能够完全沉淀IGF-II预标记受体。这两种类型的抗体均与大鼠脂肪组织、脑、心脏、肾脏、肺和脾脏中的IGF-II受体发生反应。然而，与其他物种几乎没有交叉反应。受体抗体抑制IGF-II与微粒体膜和质膜结合能力的比较表明，两种膜制剂中的IGF-II受体存在特异性免疫差异。
