Hammonds R G, Ferrara P, Li C H
Proc Natl Acad Sci U S A. 1981 Apr;78(4):2218-20. doi: 10.1073/pnas.78.4.2218.
Specific binding of human beta-endorphin to NG108-15 cells is described; human beta-[Tyr27-3H2] endorphin was used as the ligand. The binding is time dependent and saturable; Kd = 0.3 nM and ka = 1.8 x 10(8) M-1 min-1. Under the conditions optimal for beta-endorphin binding, leucine-enkephalin has one-fourth to one-third as many binding sites as beta-endorphin and its affinity is 7--10% that of beta-endorphin. Monovalent and divalent cations potently inhibit binding. Trypsin, phospholipase A, and N-ethylmaleimide reduce the ability of NG108-15 cells to bind beta-endorphin. beta-Endorphin analogs are able to fully inhibit the binding of beta-[Tyr27-3H2]endorphin, although enkephalins, morphine, and naloxone inhibit only 50--80%.
本文描述了人β-内啡肽与NG108-15细胞的特异性结合；使用人β-[酪氨酸27-3H2]内啡肽作为配体。这种结合具有时间依赖性且可饱和；解离常数Kd = 0.3 nM，结合速率常数ka = 1.8×10(8) M-1 min-1。在β-内啡肽结合的最佳条件下，亮氨酸脑啡肽的结合位点数量是β-内啡肽的四分之一到三分之一，其亲和力是β-内啡肽的7%-10%。单价和二价阳离子强烈抑制结合。胰蛋白酶、磷脂酶A和N-乙基马来酰胺降低NG108-15细胞结合β-内啡肽的能力。β-内啡肽类似物能够完全抑制β-[酪氨酸27-3H2]内啡肽的结合，而脑啡肽、吗啡和纳洛酮仅能抑制50%-80%。
