Amino-acids and peptides. Part 46. Synthesis of bradykinin analogues modified in the vicinity of the carboxy-group

Abstract

In order to investigate further the effect on biological activity of structural changes in the vicinity of the terminal carboxy-group, the following analogues of bradykinin have been synthesised by the picolyl ester method: bradykinyl-L-isoleucine (2), -L-alanine (3), and -β-alanine (4); [9-L-argininol]-bradykinin (5), [9-O-acetyl-L-argininol]-bradykinin (7), [9-β-homoarginine]-bradykinin (6), and bradykinin heptyl ester (8). The biological activities of these analogues on the isolated guinea-pig ileum and rat uterus are reported; the results confirm the marked reduction in activity caused by structural changes in this area.