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Dielectric relaxation of DNA solutions. II
Author(s) -
Sakamoto Masanori,
Hayakawa Reinosuke,
Wada Yasaku
Publication year - 1978
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.1978.360170609
Subject(s) - dielectric , chemistry , relaxation (psychology) , dipole , counterion , dielectric loss , moment (physics) , ion , viscoelasticity , analytical chemistry (journal) , thermodynamics , nuclear magnetic resonance , chromatography , physics , quantum mechanics , organic chemistry , psychology , social psychology
Real and imaganiry parts of complex dielectric constant of dilute solutions of DNA in 10 −3 M NaCl with molecular weight ranging from 0.4 × 10 6 to 4 × 10 6 were measured at frequencies from 0.2 Hz to 30 kHz. Dielectric increments Δε were obtained from Cole‐Cole plots and relaxation times τ D from the loss maximum frequency. The τ D of all samples agrees well with twice of the maximum viscoelastic relexation time in the Zimm theory, indicating that the low‐frequency dielectric relaxiation should be ascribed to be the rotation of DNA. The rms dipole moment, which was obtained from Δε, agree well with that calculated from the counterion fluctuation theory. The dielectric increment was found to be greatly depressed in MgCl 2 , which is resonably interpreted in terms of a strong binding of Mg ++ ions with DNA.