作者:David Blomberg、Paul Kreye、Chris Fowler、Kay Brickmann、Jan Kihlberg
DOI:10.1039/b515618a
日期:——
A cyclic Leu-enkephalin mimetic containing a 7-membered ring, and two linear analogues, has been prepared on solid phase. In the cyclic mimetic the intramolecular (1–4) hydrogen bond found in crystalline Leu-enkephalin has been replaced by an ethylene bridge. In addition, the amide bond between Tyr1 and Gly2 has been replaced by a methylene ether isostere and Gly3 has been deleted. The two linear analogues both contain the methylene ether isostere instead of the Tyr1-Gly2 amide bond and the shorter of the two lacks Gly3. The three compounds, and a β-turn mimetic analogous to the 7-membered turn mimetic but with Gly3 included, were evaluated for specific binding to μ- and δ-opioid receptors in rat brain membranes. With the exception of the β-turn mimetic the three other Leu-enkephalin analogues all bound with varying affinity to the μ- and δ-opioid receptors. From the results it could be concluded that Leu-enkephalin binds in a turn conformation to the opiate receptors, but that this conformation is not a (1–4) β-turn.
一种含七元环的环状亮氨酸脑啡肽模拟物及两种线性类似物已通过固相合成制备。在环状模拟物中,结晶态亮氨酸脑啡肽中的分子内(1–4)氢键被乙烯桥取代。此外,酪氨酸1和甘氨酸2之间的酰胺键被甲撑醚同位素取代,且甘氨酸3被删除。两种线性类似物均含有甲撑醚同位素,而非酪氨酸1-甘氨酸2的酰胺键;其中较短者缺乏甘氨酸3。这三种化合物以及一种类似于七元环转折模拟物但包含甘氨酸3的β-转折模拟物,均在鼠脑膜中针对μ-和δ-阿片受体的特异性结合进行了评估。除β-转折模拟物外,其他三种亮氨酸脑啡肽类似物均以不同亲和力结合到μ-和δ-阿片受体。结果表明,亮氨酸脑啡肽以转折构象结合于阿片受体,但此构象并非(1–4)β-转折。