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Electric birefringence of native DNA in an alternating field
Author(s) -
Miller Stephen J.,
Wetmur James G.
Publication year - 1974
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.1974.360130107
Subject(s) - birefringence , chemistry , relaxation (psychology) , electric field , viscosity , field strength , analytical chemistry (journal) , ionic strength , dna , field (mathematics) , thermodynamics , optics , chromatography , biochemistry , aqueous solution , physics , psychology , social psychology , mathematics , quantum mechanics , magnetic field , pure mathematics
The relaxation of the birefringence of native DNA in solution was investigated in a pulsed sine‐wave electric field. Relaxation times were calculated from the degree of damping of the birefringence signal and were studied as a function of the strength and frequency of the applied field, the molecular weight of the DNA, and the viscosity and ionic strength of the solvent. Relaxation times decrease with increasing field strength. For high‐molecular weight DNA (>10 6 daltons), the relaxation times decreased with frequency and increased less than linearly with viscosity. For low‐molecular‐weight DNA (<6 × 10 5 daltons), the relaxation times were independent of frequency, increased linearly with viscosity, and varied with the 1.65 ± 0.1 power of the molecular weight. The average birefringence of high‐molecular‐weight DNA decreased with frequency in 0.001 M Na 2 EDTA plus NaOH, pH 7.0, but is much less frequency‐dependent if the EDTA concentration is reduced tenfold, while the average birefringence of sonicated DNA increases in both solvents with increasing frequency.