Aspergillus niger glucoamylase (GA) consists of a catalytic domain and a starch-binding domain (SBD). SBD has two starch-binding sites, Sites 1 and 2. SBD can be isolated as a fragment protein. This calorimetric study aimed to examine the possibility of interactions between the two domains in a GA molecule and between the two binding sites of SBD [Biochemistry 38, 6300 (1999) and Eur. J. Biochem. 225, 133 (1994)] upon binding of a substrate analog, β-cyclodextrin (β-CD). The thermodynamic parameters of the binding of β-CD to the SBD fragment were virtually the same as those to SBD in the GA molecule. The values of the dissociation constants were 12–14 μM for Site 1 and 2 μM for Site 2, irrespective of the SBD fragment and SBD in the GA molecule. This result suggested that there was no inter-domain interaction between SBD and the catalytic domain for the binding of β-CD. In addition, amino acid mutation at one binding site did not affect the thermodynamic parameters at the other site. It was found that there is no interaction between the two binding sites in SBD and β-CD binds to Sites 1 and 2 independently.

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The annealing effects are studied based on the comparison between the experimental results and the calculated ones by the phenomenological model equation with parameters obtained by the quasi-isothermal temperature modulated differential scanning calorimetry. We have clarified that the shift of the maximum temperature in specific heat toward low and high temperatures with annealing time originates from the two effects produced by the annealing; the decay of enthalpy toward the equilibrium and an increase in the relaxation time during annealing. We have also clarified the origin of two maxima in specific heat observed at high and low temperatures in the glass transition region in the annealing experiments in polymethyl methacrylate(PMMA). The higher maximum originates from the history of cooling and heating, and the lower one, from the annealing history. We have proposed that the apparently different behavior in enthalpy relaxation in polystyrene and PMMA is originated from the same mechanism.

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During processing and preservation, various physical changes (e.g., melting, crystallization, glass transition, and complex formation) occur in food products, which affect their quality. Thermal analysis is useful to understand the physical changes. This article focuses on the effect of starch melting and glass transition on the quality of cookie. Melting temperature of starch increased with decreasing water content of the cookie dough. When starch melting during baking was prevented by pre-dehydrated baking and/or stepwise baking, in vitro starch digestibility of cookie was reduced. This is because crystalline form is more resistant to enzymatic action than the amorphous form. Reduction of starch digestibility has attracted much attention in recent years with respect to potential beneficial effects on metabolic responses. Amorphous part of cookie products is commonly in a glass state, and glass to rubber transition occurs by water sorption. Then, brittle texture of cookie changes to a ductile one. Glass transition temperature of cookie was modified by the addition of low-molecular carbohydrates. This result suggests that sugar composition plays an important role in the texture properties of cookie samples.

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In spin frustrated systems, the interplay between spin and lattice degrees of freedom, known as spin-lattice coupling, often plays an important role. This article introduces the lattice behavior in pyrochlore-based frustrated magnets with strong spin-lattice coupling. Frustrated compounds are extensively investigated through neutron scattering experiments in terms of the spin behavior, although the lattice behavior has not been carefully investigated.Assuming the presence of strong spin-lattice coupling, a detailed study on the lattice behavior should provide not only insights into lattice properties but also profound understanding of spin properties. Here, we present the results of thermodynamic studies on chromium spinels CdCr₂O₄ and CoCr₂O₄, and pyrochlore Tb₂Ti₂O₇. They exhibit characteristic lattice behaviors corresponding to their spin behaviors. Furthermore, the combination of heat capacity and thermal expansion studies provides valuable insights on the spin behavior and phase stability as well as the lattice property.

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The excess enthalpy H^E_m is important in order to understand the mixed state of fluids and intermolecular interaction. The behaviors of H^E_m of a binary mixture in the liquid state, near the critical points and gas state are quite different each other. In this article, the characteristics of the behaviors of H^E_m in each state are summarized briefly, and the cause of the difference in each characteristic is discussed in terms of the difference of the main factor of intermolecular interactions affecting the behavior of H^E_m. At first, the behaviors of H^E_m of binary mixtures containing aromatic or alcoholic molecular are described. The influences of the π-π interaction and the hydrogen bond on H^E_m are discussed over a wide range of temperature and pressure in the liquid state. Next, the specific behavior of H^E_m at near the critical points are discussed with respect to the relation of the experimental states of H^E_m to the location of the critical points, the vapor pressure curves and their extended curves of component fluids on the p-T plane. Finally, The contribution of the dipole moment and the polarizability of component molecules to the behaviors of H^E_m at gas state is discussed by comparing H^E_m of polar molecules + benzene or cyclohexane mixtures.

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Many issues have been found to be addressed for the interactions between drugs and their target proteins in the small molecule drug discovery, e.g. low efficiency of lead construction and off-target effect with low specificity; these are due to limited physicochemical information on the drug-protein interactions. In the true molecular target-based drug discovery, hit, seed, and lead compounds should show high binding affinity and specific inhibition activity. To obtain the correct interaction profiles of small compounds with a target protein, technical development of physicochemical approaches (biophysical methods) for the interactions is essential for the next generation molecular target-based drug discovery. Thermodynamic analysis using Isothermal Titration Calorimetry (ITC) is one of the representative biophysical methods, since it can monitor the direct binding of compounds with thermal reaction and discuss the binding specificity. Calorimetric analysis using ITC has recently been an attractive approach in the fields of the small molecule drug discovery. In this review, our recent studies for the small-molecule drug screening were introduced, where the inhibitors for target proteins were validated using ITC. Furthermore, we demonstrate that ITC analysis is the potential selection of validated hits and lead compounds in PPI screening.

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