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Counter‐ion‐specific helix formation of poly(γ‐methyl L ‐glutamate) derivatives containing sulfonate group in aqueous alcohols
Author(s) -
Ando Akihiro,
Satoh Mitsuru
Publication year - 2001
Publication title -
polymer international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.592
H-Index - 105
eISSN - 1097-0126
pISSN - 0959-8103
DOI - 10.1002/pi.714
Subject(s) - sulfonate , helix (gastropod) , aqueous solution , chemistry , counterion , polyelectrolyte , polymer chemistry , solvent , ion , medicinal chemistry , stereochemistry , organic chemistry , polymer , sodium , ecology , snail , biology
Charged polypeptides containing sulfonate groups were prepared by transesterification of poly(γ‐methyl L ‐glutamate) with isethionic acid. The coil–helix transition of the sulfonated polypeptides was investigated in aqueous alcohols. Marked counter‐ion specificity was observed for helix formation: Li + < Na + < Cs + ≦ Rb + ≦ K + ; this was different to that for poly( L ‐glutamate) (PLG): Cs + ≪ K + < Li + < Na + . Specific helix stabilization by counter‐ion mixing, which has been found for the PLG system, was not observed for the sulfonated polypeptides. The counter‐ion‐ and solvent‐specific helix formation is discussed and compared with that in PLG. © 2001 Society of Chemical Industry