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目的考察人结直肠肿瘤细胞株DLD - 1上甘氨酸延伸型胃泌素受体的结合特性 ;与CCK -A和CCK -B比较 ,找出不同之处。 方法 12 5Ⅰ标记甘氨酸延伸型胃泌素 ,反相高压液相纯化。用DLD - 1细胞进行受体结合试验 ,检测甘氨酸延伸型胃泌素受体结合试验受金属离子K+、Mg2 +、Al3+及温育温度、时间的影响 ;拮抗剂竞争抑制试验比较各种拮抗剂的作用。 结果金属离子K+、Mg2 +能提高甘氨酸延伸型胃泌素受体的特异结合 ,以10 0mmol/LTrisHCl缓冲液中含 10 0mmol/LK+,2mmol/LMg2 +为最佳 ;缓冲液含二个蛋白酶抑制剂时的最大结合发生在 37℃温育 90min ;没有蛋白酶抑制剂的最大结合发生在 37℃温育 6 0min。甘氨酸延伸型胃泌素受体的结合不被特异性CCK -A受体拮抗剂或特异性CCK -B受体拮抗剂拮抗 ,能被非特异性胃泌素受体拮抗剂benzotript拮抗。结论甘氨酸延伸型胃泌素受体的结合特性不同于CCK -A或CCK -B受体。DLD - 1细胞上的甘氨酸延伸型胃泌素受体既能与甘氨酸延伸型胃泌素结合 ,也能与酰胺化胃泌素结合 ,是一个不同于CCK -A和CCK -B的受体
Objective To investigate the binding characteristics of glycine - extended gastrin receptors in human colorectal cancer cell line DLD - 1, and to find out the differences with CCK - A and CCK - B. Method 12 5 Ⅰ labeled glycine extended gastrin, RP-HPLC purification. Receptor binding assay was performed on DLD - 1 cells to test the effect of glycine - extended gastrin receptor binding assay on metal ion K +, Mg2 +, Al3 + and incubation temperature and time. Antagonist competitive inhibition test was performed to compare various antagonists Role. Results K +, Mg2 + could increase the specific binding of glycine extended type gastrin receptors, with 10 0 mmol / L K + and 2 mmol / L Mg2 + in 10 0 mmol / L Tris HCl buffer being the best. The buffer contained two protease inhibitors The maximum binding of the agent occurred at 37 ° C for 90 min; no maximal protease inhibitor binding occurred at 37 ° C for 60 min. Glycine-extended gastrin receptor binding is not antagonized by a specific CCK-A receptor antagonist or a specific CCK-B receptor antagonist and antagonized by a non-specific gastrin receptor antagonist benzotript. Conclusions The glycine-extended gastrin receptor binds differently than CCK-A or CCK-B receptors. The glycine-extended gastrin receptor on DLD-1 cells, which binds to both glycine-extended gastrin and amidated gastrin, is a different receptor from CCK-A and CCK-B