title: The role of position 4 in angiotensin II antagonism: a structure-activity study.
abstract: A number of [Sar1,(pX)Phe4]-ANG II and [Sar1,(pX)Phe4,Ile8]-ANG II analogues were prepared. A good correlation between pX structure in [Sar1,(pX)Phe4]-ANG II and antagonist activity could not be found. However, the data suggest a general trend: Position 4 para substituents that are hydrophilic and capable of donating a hydrogen atom in a hydrogen bond promote agonist activity, while para substituents that are hydrophobic and incapable of donating a hydrogen atom promote antagonist activity. These properties were found to be optimal in the p-chloro substituent. The resulting analogue [Sar1,(pCl)Phe4]-ANG II is a potent ANG II antagonist in vivo. The pX substituents that promote antagonist activity in the [Sar1,(pX)Phe4]-ANG II series were unfavorable in [Sar1,(pX)Phe4,Ile8]-ANG II analogues. ANG II analogues that are antagonists by virtue of an alteration in position 8 require a position 4 agonist side chain. Concurrent modifications of positions 4 and 8 do not give rise to potent antagonists with reduced partial agonist activity.
authors.affiliation: Smith Kline and French Laboratories, Peptide Chemistry Department, King of Prussia, Pennsylvania 19406-0939.
authors.forename: J
authors.initials: J
authors.lastname: Samanen
authors.forename: T
authors.initials: T
authors.lastname: Cash
authors.forename: D
authors.initials: D
authors.lastname: Narindray
authors.forename: E
authors.initials: E
authors.lastname: Brandeis
authors.forename: T
authors.initials: T
authors.lastname: Yellin
authors.forename: D
authors.initials: D
authors.lastname: Regoli
mesh_terms: D000804:Angiotensin II / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors* / Q000138:chemical synthesis / Q000494:pharmacology; D055598:Chemical Phenomena; D002621:Chemistry; D006860:Hydrogen Bonding; D013329:Structure-Activity Relationship
chemical_list: D000804:Angiotensin II; C059977:angiotensin II, Sar(1)-Phe(4)-Ile(8)-; C059978:angiotensin II, Sar(1)-Phe(4)-