Premium
Viscosity study of DNA
Author(s) -
Scruggs Robert L.,
Ross Philip D.
Publication year - 1964
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.360020608
Subject(s) - chemistry , viscosity , limiting , ionic strength , intrinsic viscosity , relative viscosity , reduced viscosity , salt (chemistry) , ionic bonding , dna , inherent viscosity , aqueous solution , analytical chemistry (journal) , thermodynamics , ion , chromatography , biochemistry , organic chemistry , polymer , mechanical engineering , physics , engineering
The intrinsic viscosity of DNA (salmon sperm, calf thymus, T4 phage) in the presence of univalent cations decreases in a continuous manner as the ionic strength is increased and then attains a characteristic limiting value for each cation. Between 0.1 and 0.5 M the intrinsic viscosity is independent of cation, while at high salt concentration the order of decreasing limiting viscosity is K + , Na + , Li. + The intrinsic viscosity of T4 bacteriophage DNA decreases with increasing Mg ++ concentration and in 0.1 M MgCl 2 attains a value one‐half of that found in 0.2 M NaCl. Slightly beyond 0.1 M MgCl 2 spontaneous growth of birefringent fibers takes place, and upon further addition of Mg ++ these fibers redissolve to form a transparent gel of higher viscosity. The observed Huggins' constants pass through a maximum with increasing salt concentration for all of the ions studied. It is demonstrated that the concentration dependence of the reduced viscosity may be abolished and regenerated by the introduction and removal of trace amounts of basic proteins, polypeptides and polyamines. The viscosity behavior observed with the deliberately contaminated DNA samples resembles most of that reported in earlier viscosity studies, indicating that a large body of previous work on DNA probably was performed on impure material.