In order to study the effect of N-methylation of a potent enkephalin analog, H-Tyr-D-Ala-Gly-Phe-NHNH-CO-CH2CH3, on analgesic activity, six new analogs were synthesized in which one or more of amino acid residues and the acyl-hydrazide constituting the tetrapeptide acyl-hydrazide were N-methylated. N-Methylation of both Tyr at position 1 and Phe at position 4 of the analog led to a derivative which was twice as potent as morphine. On the other hand, N-methylation of D-Ala at position 2, Gly at position 3 or NHNH-CO-CH2CH3 at position 5 markedly decreased the analgesic potency. Five analogs with a modified tyrosine residue at position 1 of the tetrapeptide acyl-hydrazide were also synthesized in order to assess the role of the N-terminal Tyr residue in the biological activity.
为了研究强效
脑啡肽类似物 H-Tyr-D-Ala-Gly-Phe-NHNH-CO-CH2CH3的 N-
甲基化对镇痛活性的影响,我们合成了六种新的类似物,其中一个或多个
氨基酸残基和构成四肽酰
肼的酰基被 N-
甲基化。将类似物中位于 1 号位置的 Tyr 和位于 4 号位置的 Phe N-
甲基化后,得到的衍
生物的药效是
吗啡的两倍。另一方面,第 2 位 D-Ala、第 3 位 Gly 或第 5 位 NHNH-CO-CH2CH3 的 N-
甲基化会明显降低镇痛效力。为了评估 N 端 Tyr 残基在
生物活性中的作用,我们还合成了五种在四肽酰
肼的第 1 位修饰了
酪氨酸残基的类似物。