Some Evidences for a Conformational Change of Polypeptide Induced by Strong Electric Fields
A newly constructed electro-optical apparatus equipped with a 15 kV, 10 ms rectangular or reversing pulse generator, an AD converter and a mini-computor was used for finding a conformational change of polypeptide (PBLG) in the helix-coil transition region induced by strong electric fields. Birefringence measurements were used as the proof. When the pulse width was longer than two milliseconds, the Joule heating effect was more dominant than the effect sought. By use of PBLG with lower molecular weight, Kerr signals free from Joule heating could be observed. Field strength dependencies of steady state birefringence showed clear abnormality in the transition region, strongly suggesting the desired effect. Abnormalities which also suggest the presence of the effect were observed in the initial part of the rise and decay of the signal.
KeywordsJoule Heating Strong Electric Field Initial Rise Dichloroacetic Acid Birefringence Measurement
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