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Enthalpy of helix–coil transitions from heats of solution. I. Polyglutamates.
Author(s) -
Giacometti Giovanni,
Turolla Angelo,
Boni Renzo
Publication year - 1968
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.1968.360060315
Subject(s) - chemistry , enthalpy , solvent , helix (gastropod) , thermodynamics , electromagnetic coil , enthalpy change of solution , composition (language) , calorimetry , organic chemistry , ecology , linguistics , physics , philosophy , biology , snail , electrical engineering , engineering
The heat of solution of a series of three polyglutamates as a function of solvent composition was measured. The abrupt increase in heat of solution at the solvent composition of the helix–coil transition (as evidenced by optical rotation data) allows the estimation of the transition enthalpy change. The difference of side chain in the three polyglutamates has no appreciable effect on the transition enthalpy, although it affects the helix stability, as judged from the solvent composition at the transition points. These facts are discussed on the basis of existing models of the transition.