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Heats of thermally induced helix–coil transitions of DNA in aqueous solution
Author(s) -
Shiao D. D. F.,
Sturtevant J. M.
Publication year - 1973
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.1973.360120810
Subject(s) - chemistry , aqueous solution , enthalpy , differential scanning calorimetry , base (topology) , heat capacity , proton , salt (chemistry) , calorimetry , helix (gastropod) , base pair , melting temperature , atmospheric temperature range , dna , thermodynamics , analytical chemistry (journal) , organic chemistry , biochemistry , mathematical analysis , ecology , physics , materials science , mathematics , quantum mechanics , biology , snail , composite material
Thermal denaturation of calf thymus DNA at both alkaline and neutral pH values was studied by differential scanning calorimetry. It was shown that the dependence of the enthalpy of transition on pH and salt concentration could be accounted for on the basis of a heat capacity change of +40 cal deg −1 (base pair) −1 . In the pH range between 10.3 and 11.3, a release of 0.6 proton per base pair was calculated from the pH dependence of the melting temperature. The heat effect associated with the release of this proton was calculated to be 5 kcal mole −1 .