Synthesis and Biological Activity of Peptides Related to Eledoisin. II. Hexapeptide Amides Containing<i>N</i>-Methylamino Acids
作者:Hiroshi Sugano、Ko Higaki、Muneji Miyoshi
DOI:10.1246/bcsj.46.231
日期:1973.1
Eledoisin-like hexapeptides were synthesized in order to obtain longer-lasting hypotensive analogs. A part of the amino acid of the standard pep tide, H–Lys–Phe–Ile–Gly–Leu–Met–NH2 (1), was replaced by N-methylamino acid. It was found, in these syntheses, that when the C-terminal amino acid of a carboxy component was an N-methylamino acid, a system of dicyclohexylcarbodiimide plus 1-hydroxybenzotriazole was a useful coupling agent. With regard to the hypotensive effect in rabbits, H–Lys–Phe–Melle–Gly–Leu–Met–NH2 (2) and H–Lys–Phe–Ile–Gly–Melle–Met–NH2 (6) show much less activity; H–Lys–MePhe–Ile–Gly–Leu–Met–NH2 (3) and H–Lys–MePhe–Ile–Gly–MeLeu–Met–NH2 (7) show a substantial activity, though weaker than the standard one. On the other hand, H–Lys–Phe–Ile–Gly–MeLeu–Met–NH2 (5) and H–Lys–Phe–Ile–Sar–Leu–Met–NH2(4) show a higher activity than 1. These results indicate that, in some cases, the replacement of an amide bond by an N-methylamide bond without any change in the side chain of amino acid would have an important influence on the activity. The duration of the action of N-methypeptildes synthesized was unexpectedly of the same order of magnitude as that of 1.
为获得更持久降压效果的模拟物,合成了促咽激素样六肽。将标准肽H-Lys-Phe-Ile-Gly-Leu-Met-NH2(1)中的部分氨基酸替换为N-甲基氨基酸。在这些合成中,发现当羧基部分C末端氨基酸为N-甲基氨基酸时,二环己基碳二亚胺加1-羟基苯并三唑是一种有用的偶联剂。关于对兔子的降压效果,H-Lys-Phe-Melle-Gly-Leu-Met-NH2(2)和H-Lys-Phe-Ile-Gly-Melle-Met-NH2(6)的活性大大降低;H-Lys-MePhe-Ile-Gly-Leu-Met-NH2(3)和H-Lys-MePhe-Ile-Gly-MeLeu-Met-NH2(7)显示出相当的活性,尽管弱于标准肽。另一方面,H-Lys-Phe-Ile-Gly-MeLeu-Met-NH2(5)和H-Lys-Phe-Ile-Sar-Leu-Met-NH2(4)的活性高于1。这些结果表明,在某些情况下,将酰胺键替换为N-甲基酰胺键而不改变氨基酸侧链会对活性产生重要影响。合成的N-甲基肽的作用持续时间与1相当。