Yaoi Y, Hashimoto K, Takahara K, Kato I
Biology Division, National Cancer Center Research Institute, Tokyo, Japan.
Exp Cell Res. 1991 Jun;194(2):180-5. doi: 10.1016/0014-4827(91)90351-t.
The abilities of eight extracellular matrix proteins, fibronectin, vitronectin, laminin, and collagen types I, II, III, IV, and V to bind insulin were examined by binding studies with insulin conjugated with peroxidase. At a physiological pH and ionic strength, type V collagen bound to insulin most strongly. The other types of collagen, laminin, and vitronectin also bound insulin with affinity lower than that of type V collagen. The insulin-binding site of type V collagen was in a 30-kDa CNBr fragment of the alpha 1 (V) chain. Analysis of the amino acid sequence showed that this 30-kDa fragment was identical to the heparin-binding fragment of type V collagen. The insulin-binding sites of laminin and vitronectin were located in the A chain and in the heparin-binding domain, respectively. Insulin bound to type V collagen stimulated the synthesis of DNA by mouse mammary tumor MTD cells, indicating that bound insulin retained mitogenic activity.
通过与过氧化物酶偶联的胰岛素进行结合研究，检测了八种细胞外基质蛋白（纤连蛋白、玻连蛋白、层粘连蛋白以及I、II、III、IV和V型胶原蛋白）结合胰岛素的能力。在生理pH值和离子强度下，V型胶原蛋白与胰岛素的结合最为强烈。其他类型的胶原蛋白、层粘连蛋白和玻连蛋白也能结合胰岛素，但其亲和力低于V型胶原蛋白。V型胶原蛋白的胰岛素结合位点位于α1(V)链的一个30 kDa的溴化氰片段中。氨基酸序列分析表明，这个30 kDa的片段与V型胶原蛋白的肝素结合片段相同。层粘连蛋白和玻连蛋白的胰岛素结合位点分别位于A链和肝素结合结构域。与V型胶原蛋白结合的胰岛素刺激小鼠乳腺肿瘤MTD细胞的DNA合成，表明结合的胰岛素保留了促有丝分裂活性。
