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Ion transport through liquid membrane by cyclic octapeptides
Author(s) -
Kimura Shunsaku,
Imanishi Yukio
Publication year - 1984
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.360230310
Subject(s) - chemistry , cyclic peptide , chloroform , membrane , aqueous solution , picrate , peptide , phase (matter) , alkali metal , ion transporter , ion , stereochemistry , inorganic chemistry , medicinal chemistry , chromatography , organic chemistry , biochemistry
Cation transport through a chloroform liquid membrane by cyclic octapeptides—cyclo(Leu‐Pro) 4 , cyclo(Phe‐Pro) 4 , and cyclo[Lys(Z)‐Pro] 4 —was investigated. All of these cyclic octapeptides transported K + and Ba 2+ , and the rate of cation transport was correlated with the ability to extract cations from the aqueous phase to the chloroform phase. Among them, cyclo (Leu‐Pro) 4 was the most efficient and transported K + and Ba 2+ selectively from other alkali and alkaline earth cations, respectively. The rate of K + transport by cyclo(Leu‐Pro) 4 was about one‐third as fast as that by dicyclohexyl 18‐crown‐6. Picrate anion transport against its concentration gradient was observed by cyclo(Leu‐Pro) 4 , which is conjugated with the selective transport of K + . Complex formation in a liposome between cyclo(Leu‐Pro) 4 and Ba 2+ was observed, but the binding constant was low.