Kamikubo K, Murase H, Murayama M, Miura K, Nozaki M, Tsurumi K
Regul Pept. 1986 Sep;15(2):155-62. doi: 10.1016/0167-0115(86)90085-6.
Binding of human beta-endorphin (beta h-EP) to bovine adrenal medullary membranes was characterized using [125I]Tyr27-beta h-EP [( 125I]beta h-EP) as a primary ligand. The specific binding of [125I]beta h-EP was time-dependent, saturable and stereospecific. Analysis of a saturation isotherm revealed two apparent classes of specific binding sites with dissociation constants of 2.4 and 34 nM. The extent of maximum inhibition of specific [125I]beta h-EP binding by either levorphanol, morphine, naloxone, dynorphin A (1-13) or D-Ala2-D-Leu5-enkephalin was similar to each other and remained partial (60-70%). Levorphanol eliminated the high affinity component but showed no effect on the low affinity component of [125I]beta h-EP binding. beta h-EP(1-31) displaced completely the [125I]beta h-EP binding. However, beta h-EP(1-23) only partially (approximately 80%) inhibited the [125I]beta h-EP binding. beta h-EP(6-31) showed inhibitory activity on [125I]beta h-EP binding. These results suggest that [125I]beta h-EP binding to bovine adrenal medullary membranes consists of a high affinity opioid-sensitive component and a low affinity non-opioid component. The non-opioid component of [125I]beta h-EP binding may be related to COOH-terminal of the beta h-EP molecule.
使用[125I]酪氨酸27-β人内啡肽（[125I]β人内啡肽）作为主要配体，对人β-内啡肽（βh-EP）与牛肾上腺髓质膜的结合特性进行了表征。[125I]βh-EP的特异性结合具有时间依赖性、饱和性和立体特异性。对饱和等温线的分析揭示了两类明显的特异性结合位点，其解离常数分别为2.4和34 nM。左啡诺、吗啡、纳洛酮、强啡肽A（1-13）或D-丙氨酸2-D-亮氨酸5-脑啡肽对特异性[125I]βh-EP结合的最大抑制程度彼此相似，且仍为部分抑制（60-70%）。左啡诺消除了[125I]βh-EP结合的高亲和力成分，但对低亲和力成分无影响。βh-EP（1-31）完全取代了[125I]βh-EP的结合。然而，βh-EP（1-23）仅部分（约80%）抑制[125I]βh-EP的结合。βh-EP（6-31）对[125I]βh-EP结合具有抑制活性。这些结果表明，[125I]βh-EP与牛肾上腺髓质膜的结合由高亲和力阿片类敏感成分和低亲和力非阿片类成分组成。[125I]βh-EP结合的非阿片类成分可能与βh-EP分子的羧基末端有关。
