Biopolym. Cell. 1989; 5(5):31-37.
Structure and Function of Biopolymers
The effect of [Na+] ions concentration on the enthalpy of DNA helix-coil transition
1Karapetyan A. T., 2Vardevanyan P. O., 3Frank-Kamenetskii M. D.
  1. Kirovokan State Pedagogical Institute
    Kirovokan, USSR
  2. Yerevan State University, Department of Molecular Physics and Biophysics,
    Yerevan, USSR
  3. Institute of Molecular Genetics, Academy of Sciences of the USSR
    Moscow, USSR


The enthalpy (AH) of the helix-coil transition of different QC-content DNAs is obtained by means of the «tie calorimetry» and «areas» methods. The data obtained experimentally show that the slope of the dependence of AH on lg[Na+] decreases with an increase of the GC-content of DNA.


[1] Krakauer H, Sturtevant JM. Heats of the helix-coil transitions of the poly A-poly U complexes. Biopolymers. 1968;6(4):491-512.
[2] Wartell RM. The helix-coil transitions of poly (dA)-poly (dT) and poly (dA-dT)-poly (dA-dT). Biopolymers. 1972;11(4):745-59.
[3] Gruenwedel DW. Salt effects on the denaturation of DNA. IV. A calorimetric study of the helix-coil conversion of the alternating copolymer poly[d(A-T)]. Biochim Biophys Acta. 1975;395(3):246-57.
[4] Privalov PL, Ptitsyn OB, Birshtein TM. Determination of stability of the DNA double helix in an aqueous medium. Biopolymers. 1969;8(5):559–71.
[5] Klump H, Ackermann T. Experimental thermodynamics of the helix--random coil transition. IV. Influence of the base composition of DNA on the transition enthalpy. Biopolymers. 1971;10(3):513-22.
[6] Gruenwedel DW. Salt effects on the denaturation of DNA. 3. A calorimetric investigation of the transition enthalpy of calf thymus DNA in Na2SO4 solutions of varying ionic strength. Biochim Biophys Acta. 1974;340(1):16-30.
[7] Mrevlishvili GM. Low-temperature calorimetry of biological macromolecules. Usp fiz nauk. 1979; 128(2):273-312.
[8] Lazurkin YS, Frank-Kamenetskii MD, Trifonov EN. Melting of DNA: its study and application as a research method. Biopolymers. 1970;9(11):1253-306.
[9] Frank-Kamenetskii MD. Consideration of helix-coil transition in homoPolymers by the most Probable distribution method. Mol. Biol (Mosk). 1968;2(2):408–19.
[10] Frank-Kamenetskii MD. Theory of the helix – coil transition for deoxyribonucleic acids with additional connections between the chains. Vysokomolekulyarnye Soedineniya. 1965; 7(2):354-61.
[11] Frank-Kamenetskii MD. On the theory of melting DNA comPlexes with low molecular weight substances. Mol Biol (Mosk). 1972; 6(4):621-627.
[12] Kapanetyan AT, Permagorov VI, Frank-Kamenetskii MD, Lazurkin YuS. Thermodynamic study of DNA comPlexes with dyes. Mol Biol (Mosk). 1972; 6(6):867-73.
[13] Kapanetyan AT, Permagorov VI, Frank-Kamenetskii MD. Thermodynamic characteristics of DNA and its complexes with dyes. Conformational changes of biopolymers in solution. Moscow, Nauka, 1973; 43-8.
[14] Sidorenko NV, Kosaganov YuN. Physico-chemical studies of the interaction of DNA with RNase A. Conformational changes of biopolymers in solution. Moscow, Nauka, 1973; 57-67.
[15] Karapetyan AT, Permogorov VI. Thermodynamic investigations of complexes of DNA with cyanide dyes. Mol Biol. 1974;8(1):9-13.
[16] Poletayev AI, Ivanov VI, Minchenkova LE, Shchelkina AK. Thermodynamic characteristics of the comPlexes DNA-C+ , DNA-A+. Mol Biol (Mosk). 1968; 3(2): 303-11.
[17] Panosyan GA, Vardevanyan PO, VardaPetyan RR, KaraPetyan AT. Study of peculiarity of interaction between histones and DNAs of different origin Stud biophys. 1982. 1-91, N 3:237-238.
[18] Vardevanian PO, Babaian IuS, Vardapetian RR, Panosian GA, Aslanian VM. A simple method for the definition of average DNA nucleotide composition from melting curves. Biofizika. 1983;28(1):130-1.
[19] Marmur J. A procedure for the isolation of deoxyribonucleic acid from micro-organisms. J Mol Biol. 1961;3(2):208–18.
[20] Felsenfeld G, Hirschman SZ. A neighbor-interaction analysis of the hypochromism and spectra of DNA. J Mol Biol. 1965;13(2):407-27.
[21] Waring MJ. Complex formation between ethidium bromide and nucleic acids. J Mol Biol. 1965;13(1):269-82.
[22] Vedenov AM, Dykhne AM, Frank-Kamenetskii MD. The helix-coil transition in DNA. Usp fiz nauk. 1971; 105(3):479-519.
[23] Frank-Kamenetskii F. Simplification of the empirical relationship between melting temperature of DNA, its GC content and concentration of sodium ions in solution. Biopolymers. 1971;10(12):2623-4.
[24] Kozyavkin SA, Lyubchenko YL. The nonequilibrium character of DNA melting: effects of the heating rate on the fine structure of melting curves. Nucleic Acids Res. 1984;12(10):4339-49.