- 作者: 陳芬芳; 姜安娜; 王盈錦
- 作者服務機構: 國立陽明醫學院生化研究所
- 中文摘要: Friend 病毒感染之老鼠,其脾臟細胞曾被證實可與造血激素(Erythropoietin)作特定結合。本實驗由此種細胞抽取細胞膜,並證實此胞膜具有與造血激素作特殊結合之能力。脾細胞先在 4°C 以 lOmM Tris-Cl, pH 7.4 處理5分鐘,再把細胞磨碎、離心,除去細胞核部份,在 75,OOOg 離心90分鐘,將細胞膜沈澱出,以標示的造血激素(於醣鍊上)或是標示的造血激素作結合研究,結果顯示抽取的胞膜仍具與造血激素結合的能力。在200倍未標示的造血激素存在下,90%的結合可被抑制,其他生長因子及醣蛋白,則不能抑制結合,在25°C下,經2.5小時;37°C下,經1.5小時,結合可達平衡,而在3nM造血激素存在下,結合可達飽合,其分解常數約為1.5nM。
- 英文摘要: It has been shown that radiolabeled erythropoietin (epo) specifically binds to homogeneous epo-responsive spleen cells from mice infected with the anemic variant of the Friend virus. We now report thatmembranes isolated from these cells retain the ability to specifically bind epo. Spleen cells were swollenin ice-cold 10 mM Tris-Cl pH 7.4 containing 0.2 mM phenylmethyl sulfonylfluoride for 5 minutes, afterwhich the cells were homogenized and centrifuged to remove nuclear fraction. Membranes were collectedby centrifuging the supernatant at 75.000 g for 90 min. Utilizing H-epo labeled at the terminal sialicacids of the carbohydrate moieties or I-epo labeled at the tyrosine residues, it was shown that theisolated membranes contained specific epo binding sites. About 90% of the binding could be inhibited by thepresence of unlabeled epo whereas no inhibition was seen with other elycoprotems and growth factors.Equilibrium could be reachea in approximately 2.5 hr at 25°C or 1.5 hr at 37°C. Binding could be sa-turated at an epo concentration of about 3 nM, Scatchard analysis indicated a single class of receptors witha Kd of approximately 1.5 nM.
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