Heat Capacity Changes (ΔCp) for Interconversions between Differentially-Ordered DNA States within Physiological Temperature Domains: Implications for Biological Regulatory Switches

2020 ◽  
Vol 124 (27) ◽  
pp. 5614-5625
Author(s):  
Jens Völker ◽  
G. Eric Plum ◽  
Kenneth J. Breslauer
Keyword(s):  
Heat Capacity ◽  
Physiological Temperature ◽  
Heat Capacity Changes

scholarly journals Analysis based on scaling relations of critical behaviour at PM–FM phase transition and universal curve of magnetocaloric effect in selected Ag-doped manganites

RSC Advances ◽  
2018 ◽  
Vol 8 (33) ◽  
pp. 18294-18307 ◽  
Author(s):  
S. Tarhouni ◽  
R. M'nassri ◽  
A. Mleiki ◽  
W. Cheikhrouhou-Koubaa ◽  
A. Cheikhrouhou ◽  
...  
Keyword(s):  
Phase Transition ◽  
Heat Capacity ◽  
Magnetocaloric Effect ◽  
Critical Exponents ◽  
Critical Behaviour ◽  
Scaling Relations ◽  
Universal Curve ◽  
Magnetic Entropy ◽  
Heat Capacity Changes ◽  
Doped Manganites

The universal curves of magnetic entropy changes and heat capacity changes for Pr0.5Sr0.5−xAgxMnO3 (0 ≤ x ≤ 0.2) are obtained by using the critical exponents.

scholarly journals Thermodynamics of DNA: heat capacity changes on duplex unfolding

2019 ◽  
Vol 48 (8) ◽  
pp. 773-779 ◽  
Author(s):  
Anatoliy Dragan ◽  
Peter Privalov ◽  
Colyn Crane-Robinson
Keyword(s):  
Heat Capacity ◽  
Accessible Surface Area ◽  
Solvent Accessible Surface Area ◽  
Polar Component ◽  
Heat Capacity Change ◽  
Dna Duplex ◽  
Capacity Change ◽  
Heat Capacity Changes ◽  
Accessible Surface ◽  
Lower Magnitude

Abstract The heat capacity change, ΔCp, accompanying the folding/unfolding of macromolecules reflects their changing state of hydration. Thermal denaturation of the DNA duplex is characterized by an increase in ΔCp but of much lower magnitude than observed for proteins. To understand this difference, the changes in solvent accessible surface area (ΔASA) have been determined for unfolding the B-form DNA duplex into disordered single strands. These showed that the polar component represents ~ 55% of the total increase in ASA, in contrast to globular proteins of similar molecular weight for which the polar component is only about 1/3rd of the total. As the exposure of polar surface results in a decrease of ΔCp, this explains the much reduced heat capacity increase observed for DNA and emphasizes the enhanced role of polar interactions in maintaining duplex structure. Appreciation of a non-zero ΔCp for DNA has important consequences for the calculation of duplex melting temperatures (Tm). A modified approach to Tm prediction is required and comparison is made of current methods with an alternative protocol.

Protonation of azobenzene derivatives. I. Methyl orange and ortho-methyl orange

1973 ◽  
Vol 26 (5) ◽  
pp. 1005 ◽  
Author(s):  
PD Bolton ◽  
J Ellis ◽  
KA Fleming ◽  
IR Lantzke
Keyword(s):  
Heat Capacity ◽  
Methyl Orange ◽  
Aqueous Solutions ◽  
Standard Enthalpy ◽  
Acidity Constants ◽  
Temperature Range ◽  
Heat Capacity Changes ◽  
Azobenzene Derivatives

Thermodynamic acidity constants have been measured over the temperature range 5-50� for aqueous solutions of sodium 4?-dimethylaminoazobenzene- 4-sulphonate (methyl orange) and sodium 4?-dimethylaminoazobenzene-2- sulphonate (ortho-methyl orange). From these data values of the standard enthalpy, entropy, and heat capacity changes have been calculated for these compounds. These results are discussed in conjunction with previous spectrophotometric and other data with reference to the nature of the equilibrium systems involved in these protonation reactions. It is concluded that existing evidence does not allow an unequivocal assignment of the sites of protonation of these and related molecules.

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