Open AccessCalorimetric Studies on Melting of tRNA Phe (Yeast)
Author(s) -
HINZ HansJürgen,
FILIMONOV Vladimir V.,
PRIVALOV Peter L.
Publication year - 1977
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1977.tb11226.x
Subject(s) - differential scanning calorimetry , enthalpy , thermodynamics , chemistry , calorimetry , melting temperature , decomposition , ion , heat capacity , standard enthalpy of formation , thermal decomposition , yeast , crystallography , materials science , organic chemistry , biochemistry , physics , composite material
The heat effects involved in thermal unfolding of tRNA Phe from yeast have been determined in various buffer systems by direct differential scanning calorimetry. Perfect reversibility of the melting process has been demonstrated for measurements in the absence of Mg 2+ ions. The overall molar transition enthalpy, ΔH t = 298 ± 15 kcal mol −1 (1247 ± 63 kJ mol −1 ), has been shown to be independent of the NaCl concentration and the nature of the buffers used in this study. Δ H t is identical in the presence and in the absence of Mg 2+ ions within the margin of experimental error. This experimental result implies a vanishing or very small heat capacity change to be associated with melting. Decomposition of the calorimetrically determined complex transition curves, on the assumption that the experimental melting profile represents the sum of independent two‐state transitions, results in five transitions which have been assigned to melting of different structural domains of the tRNA.