Branch of Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Science Avenue, 6, Pushchino, Moscow Region 142290, Russia.
J Pept Sci. 2012 Feb;18(2):83-7. doi: 10.1002/psc.1417. Epub 2011 Nov 3.
Two selective agonists of nonopioid β-endorphin receptor, synthetic peptides TPLVTLFK (octarphin) and SLTCLVKGFY (immunorphin), were labeled with tritium to specific activity of 29 and 25 Ci/mmol, respectively. Both labeled peptides were found to bind to high-affinity naloxone-insensitive binding sites on the membranes isolated from the rat myocardium (Kd = 2.0 ± 0.2 and 2.5 ± 0.3 nM, respectively). The [(3)H]octarphin specific binding to the myocardial membranes was inhibited by unlabeled β-endorphin (Ki = 1.9 ± 0.2 nM) and immunorphin (Ki = 2.2 ± 0.3 nM). The [(3)H]immunorphin specific binding with the membranes was inhibited by unlabeled β-endorphin (Ki = 2.3 ± 0.3 nM) and octarphin (Ki = 2.4 ± 0.3 nM). The binding specificity study revealed that these binding sites were insensitive not only to naloxone but also to α-endorphin, γ-endorphin, [Met(5)]enkephalin and [Leu(5)]enkephalin. Thus, β-endorphin, immunorphin and octarphin bind to the common high-affinity naloxone-insensitive receptor of the rat myocardial membranes.
两种非阿片 β-内啡肽受体选择性激动剂，合成肽 TPLVTLFK（八肽啡）和 SLTCLVKGFY（免疫啡），用氚标记，比活度分别为 29 和 25 Ci/mmol。两种标记肽都被发现与大鼠心肌膜上的高亲和力纳洛酮不敏感结合位点结合（Kd 分别为 2.0 ± 0.2 和 2.5 ± 0.3 nM）。[(3)H]八肽啡与心肌膜的特异性结合被未标记的β-内啡肽（Ki = 1.9 ± 0.2 nM）和免疫啡（Ki = 2.2 ± 0.3 nM）抑制。[(3)H]免疫啡与膜的特异性结合被未标记的β-内啡肽（Ki = 2.3 ± 0.3 nM）和八肽啡（Ki = 2.4 ± 0.3 nM）抑制。结合特异性研究表明，这些结合位点不仅对纳洛酮而且对α-内啡肽、γ-内啡肽、[Met(5)]脑啡肽和[Leu(5)]脑啡肽不敏感。因此，β-内啡肽、免疫啡和八肽啡与大鼠心肌膜的共同高亲和力纳洛酮不敏感受体结合。
