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Kinetic properties and the electric field effect of life helix–coil transition of poly(γ-benzyl L-glutamate) determined from dielectric relaxation measurements

✍ Scribed by Gerhard Schwarz; Joachim Seelig

Publisher
Wiley (John Wiley & Sons)
Year
1968
Tongue
English
Weight
704 KB
Volume
6
Category
Article
ISSN
0006-3525

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✦ Synopsis

Dielectric relaxation of poly(ybenzy1 L-glutamate) in solution has been studied in the 5 kcps-10 Mcps range for various values of the helix content. The results give first experimental evidence for three effects of major significance. (1) The system exhibits dielectric relaxation due to a chemical rate process (namely helix formation). This confirms recent theoretical predictions. (2) The mean relaxation time T* of the helix-coil transition could be evaluated as a function of the degree of transition. The results are in excellent agreement with a previously developed theory. At the midpoint of transition it is found T & , = = 5 X 10-7 see. The elementary process of helical growth turns out to be practically diffusion-controlled (with a rate constant of hydrogen bond formation of 1.3 X 1010 sec-1. (3) There is a considerable electric field effect of the helix-coil transition. This indicates that conformation changes in biological systems could be potentially caused by direct action of an electric field.

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