Newman E L, Borsodi A, Toth G, Hepp F, Barnard E A
Neuropeptides. 1986 Nov-Dec;8(4):305-15. doi: 10.1016/0143-4179(86)90002-8.
A novel affinity reagent DALECK, i.e. D-Ala2-Leu5-enkephalin with a C-terminal chloromethyl ketone group, was previously synthesized in normal and in tritiated form and shown to react irreversibly at opioid receptors, with some evidence for selectivity for the mu subtype. DALECK tritiated in its phenolic group has been synthesized at 13-fold higher specific radioactivity than in the previous study. In the irreversible reaction of this product at pH 8.1 with rat brain membranes it was confirmed that only one polypeptide there is labelled, of apparent Mr 58,000. Competition between this reaction and ligands highly selective for the mu, delta or kappa binding sites yielded curves demonstrating the very high selectivity of the DALECK irreversible reaction for the mu site. The results provide evidence that the mu opioid receptor protein contains only one type of binding subunit, whose apparent Mr is 58,000, this size being dependent upon the conditions used in the gel electrophoresis and being higher when stringent conditions which would reduce all internal disulphide bonds are applied.
一种新型亲和试剂DALECK，即具有C末端氯甲基酮基团的D-丙氨酸2-亮氨酸5-脑啡肽，先前已以正常形式和氚化形式合成，并显示出在阿片受体上发生不可逆反应，有一些证据表明其对μ亚型具有选择性。酚基团被氚化的DALECK的合成比先前的研究具有高13倍的比放射性。在该产物于pH 8.1下与大鼠脑膜的不可逆反应中，证实只有一种表观分子量为58,000的多肽被标记。该反应与对μ、δ或κ结合位点具有高度选择性的配体之间的竞争产生的曲线表明，DALECK不可逆反应对μ位点具有非常高的选择性。结果提供了证据，表明μ阿片受体蛋白仅包含一种类型的结合亚基，其表观分子量为58,000，该大小取决于凝胶电泳中使用的条件，并且当应用会减少所有内部二硫键的严格条件时会更高。
