Netsu Sokutei
Online ISSN : 1884-1899
Print ISSN : 0386-2615
ISSN-L : 0386-2615
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Volume 41, Issue 1
Displaying 1-5 of 5 articles from this issue
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Preface
Review
  • Precise Calorimetry for Thermodynamic Stability and Molecular Function of Proteins
    Shun-ichi Kidokoro
    2014 Volume 41 Issue 1 Pages 2-9
    Published: January 30, 2014
    Released on J-STAGE: November 20, 2022
    DOIhttps://doi.org/10.11311/jscta.41.1_2
    JOURNAL FREE ACCESS
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    Development of precise calorimetry has enabled us to understand the stability of three-dimensional structure, catalytic activity, and molecular recognition of biomolecules. We have developed isothermal acid-titration calorimetry (IATC) to evaluate the pH dependence of protein enthalpy and demonstrated the thermodynamic transition between the native and the molten globule (MG) state of cytochrome c with very small enthalpy change (∼30 kJ/mol) by this method. The double deconvolution method with precise differential scanning calorimetry (DSC) has revealed the MG state as an equilibrium intermediate state of the reversible thermal transition of the protein and pressure perturbation calorimetry (PPC) has succeeded to determine its volumetric properties. The hydrolytic activity of cellulase against a kind of oligo-cellulose can be quantitatively evaluated using dynamic feature of isothermal titration calorimetry (ITC) and a kinetic equation for enzymatic reaction. We developed a new multi-binding model and succeeded to characterize the interaction between adenosine 5’-triphosphate and magnesium ion. These examples strongly indicate the importance of precise calorimetry in the field of protein research.
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  • Development of New Analysis Methods in Thermal Transition Kinetics
    Akihiko Toda
    2014 Volume 41 Issue 1 Pages 10-16
    Published: January 30, 2014
    Released on J-STAGE: November 20, 2022
    DOIhttps://doi.org/10.11311/jscta.41.1_10
    JOURNAL FREE ACCESS
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    Analysis methods are discussed for the thermal transition kinetics of the 1st-order phase transitions (e.g. crystallization, melting, and solid-solid phase transformation) and chemical reaction by thermal analysis using differential scanning calorimetry, DSC, with constant rate of heating (cooling) and periodic modulation in temperature. The analysis examines the heating rate dependences of the peak temperature obtained by a constant heating (cooling) of DSC and of the characteristics time of the frequency dispersion of an effective dynamic heat capacity determined by Temperature-Modulated DSC. Those dependences are from kinetic response of the transformation processes, so that shares common valuable information on the kinetics. The following transition kinetics has been examined, and the applicability of the methods has been confirmed: polymer crystallization, polymer crystal melting, isotropization transition of a nematic polymer, an epoxy thermosetting system, martensitic transformation of TiNi alloy, melting and crystallization of ice/water confined in a porous silica gel, ferroelectric transformations of P(VDF-TrFE) copolymers. The emphasis is on the application to the complex systems having broad transition region with fast kinetics: a typical example is the melting of polymer crystals.
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  • Calorimetric Studies for Standardization and Their Application to Ionic Liquids
    Yoshitaka Shimizu
    2014 Volume 41 Issue 1 Pages 17-23
    Published: January 30, 2014
    Released on J-STAGE: November 20, 2022
    DOIhttps://doi.org/10.11311/jscta.41.1_17
    JOURNAL FREE ACCESS
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    Standardization plays important roles in various fields of technology and trade for convenience and mutualrecognition. In this article, author's activities based on calorimetry and thermal analysis for the standardizationconcerning quality assurance of measurements are briefly described. For the quality assurance including establishmentof metrological traceability, certified reference materials for calibration of analytical instruments were developed byusing adiabatic calorimetry and differential scanning calorimetry (DSC). Cyclohexane was validated as a referencematerial for DSC calibration in a round robin test (RRT) conducted by the working group on standardization in JapanSociety of Calorimetry and Thermal Analysis. The RRT results indicate that appropriate calibration with suitablereference materials reduces significant biases in both temperature and enthalpy. The author also participated in aproject for standardization of ionic liquids conducted by IUPAC. Our measurement capability in calorimetry wasvalidated by agreement of our reported thermodynamic quantities of a reference ionic liquid with those by otherparticipants. Based on the validated capability, we clarified that origin of low melting point of some ionic liquids werelow entropy of crystal from the analysis of alkyl-chain-length dependences of thermodynamic quantities.
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