scholarly journals Equivalence of the Transition Heat Capacities of Proteins and DNA

2021 ◽  
Author(s):  
Matthew W Eskew ◽  
Albert S Benight
Keyword(s):  
Heat Capacity ◽  
Thermal Denaturation ◽  
Fundamental Property ◽  
Heat Capacities ◽  
Scanning Calorimetry ◽  
Protein Amino Acid ◽  
Native Proteins ◽  
Dna Base ◽  
The Individual ◽  
Transition Heat

It has been reported for many globular proteins that the native heat capacity at 25°C, per gram, is the same. This has been interpreted to indicate that heat capacity is a fundamental property of native proteins that provides important information on molecular structure and stability. Heat capacities for both proteins and DNA has been suggested to be related to universal effects of hydration/solvation on native structures. Here we report on results from thermal denaturation analysis of two well-known proteins, human serum albumin and lysozyme, and a short DNA hairpin. The transition heat capacities at the Tm for the three molecules were quantitatively evaluated by differential scanning calorimetry. When normalized per gram rather than per mol the transition heat capacities were found to be precisely equivalent. This observation for the transition heat capacities of the proteins is consistent with previous reports. However, an identical transition heat capacity for DNA has not been reported and was unexpected. Further analysis of the collected data suggested a mass dependence of hydration effects on thermal denaturation that is preserved at the individual protein amino acid and DNA base levels. Equivalence of transition heat capacities suggests the possibility of a universal role of hydration effects on the thermal stability of both proteins and DNA.

scholarly journals Excess heat capacity and entropy of mixing along the hydroxyapatite-chlorapatite and hydroxyapatite-fluorapatite binaries

2021 ◽  
Vol 48 (12) ◽  
Author(s):  
Edgar Dachs ◽  
Artur Benisek ◽  
Daniel Harlov ◽  
Max Wilke
Keyword(s):  
Heat Capacity ◽  
Low Temperature ◽  
Density Functional ◽  
Hexagonal Phase ◽  
Exchange Process ◽  
Excess Heat Capacity ◽  
Heat Capacities ◽  
Scanning Calorimetry ◽  
Excess Heat ◽  
Ideal Mixing

AbstractThe heat capacity, Cp, of synthetic hydroxyapatite [Ca5(PO4)3OH–OH-Ap], as well as of ten compositions along the OH-Ap-chlorapatite (Cl-Ap) join and 12 compositions along the OH-Ap-fluorapatite (F-Ap) join have been measured using relaxation calorimetry (heat capacity option of the Physical Properties Measurement System—PPMS) and differential scanning calorimetry (DSC) in the temperature range of 5–764 K. Apatites along the Cl-OH and F-OH joins were synthesized at 1100 °C and 300 MPa in an internally heated gas pressure vessel via an exchange process between synthetic fluorapatite or chlorapatite crystals (200–500 μm size) and a series of Ca(OH)2-H2O solutions with specific compositions and amounts relative to the starting apatite. The standard third-law entropy of OH-Ap, derived from the low-temperature heat capacity measurements, is S° = 386.3 ± 2.5 J mol−1 K−1, which is ~ 1% lower than that resulting from low-temperature adiabatic calorimetry data on OH-Ap from the 1950’s. The heat capacity of OH-Ap above 298.15 K shows a hump-shaped anomaly centred around 442 K. Based on published structural and calorimetric work, this feature is interpreted to result from a monoclinic to hexagonal phase transition. Super ambient Cp up to this transition can be represented by the polynomial: $$C_{p}^{{\text{OH - Ap}}} {}_{{298K - 442K}}\left( {{\text{J mol}}^{ - 1} {\text{K}}^{- 1}} \right) = {1013.7-13735.5T^{{ - 0.5}}} + 2.616718\,10^{7} T^{{ - 2}} - 3.551381\,10^{9} T^{{ - 3}} .$$ C p OH - Ap 298 K - 442 K J mol - 1 K - 1 = 1013.7 - 13735.5 T - 0.5 + 2.616718 10 7 T - 2 - 3.551381 10 9 T - 3 . . The DSC data above this transition were combined with heat capacities computed using density functional theory and can be given by the Cp polynomial: $$C_{p}^{{\text{OH - Ap}}} {}_{{ >\,442K}}\left( {{\text{J mol}}^{ - 1} {\text{K}}^{- 1}} \right) = {877.2-11393.7 T^{ - 0.5}} + {5.452030\,10^{7}} \,T^{- {2}} - {1.394125\,10^{10}} \,T^{- {3}}$$ C p OH - Ap > 442 K J mol - 1 K - 1 = 877.2 - 11393.7 T - 0.5 + 5.452030 10 7 T - 2 - 1.394125 10 10 T - 3 . Positive excess heat capacities of mixing, ∆Cpex, in the order of 1–2 J mol−1 K−1, occur in both solid solutions at around 70 K. They are significant at these conditions exceeding the 2σ-uncertainty of the data. This positive ∆Cpex is compensated by a negative ∆Cpex of the same order at around 250 K in both binaries. At higher temperatures (up to 1200 K), ∆Cpex is zero within error for all solid solution members. As a consequence, the calorimetric entropies, Scal, show no deviation from ideal mixing behaviour within a 2σ-uncertainty for both joins. Excess entropies of mixing, ∆Sex, are thus zero for the OH-Ap–F-Ap, as well as for the OH-Ap–Cl-Ap join. The Cp–T behaviour of the OH-Ap endmember is discussed in relation to that of the F- and Cl-endmembers.

scholarly journals THE STUDY OF THERMAL DENATURATION OF BEEF, PORK, CHICKEN AND TURKEY MUSCLE PROTEINS USING DIFFERENTIAL SCANNING CALORIMETRY

2019 ◽  
Vol 4 (3) ◽  
pp. 19-23
Author(s):  
Irina V. Agafonkina ◽  
Igor A. Korolev ◽  
Taras A. Sarantsev
Keyword(s):  
Differential Scanning Calorimetry ◽  
Heat Capacity ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Thermal Processing ◽  
Thermal Denaturation ◽  
Meat Product ◽  
Muscle Proteins ◽  
Scanning Calorimetry ◽  
Denaturation Process

In the temperature range from 45 °C to 90 °C the process of thermal denaturation of a whole complex of muscle proteins in meat takes place. An effective mode to register the thermal denaturation process is the method of differential scanning calorimetry (DSC). As a result of studies the differences during the process of thermal denaturation of muscle proteins of pork, beef, chicken and turkey were defined by the appearance of endothermic peaks in DSC thermograms. The main variances are associated with the process of denaturation of myosin and sacroplasmic proteins and indicate indirectly their quantitative ratio in meat. The values of effective specific heat capacity in the temperature range from 20 °C to 90 °C are obtained as well as those of heat spent on the denaturation process.At reheating, the values of specific heat capacity increased by 0.1 J/(g*K) on the average, and peaks of thermal denaturation were not detected, that certifies the irreversibility of the denaturation process and the decrease in the bound moisture proportion in meat after thermal processing. Knowledge of the nature of protein thermal denaturation of each kind of meat product is one of the necessary tools for developing the technology of meat product thermal processing.

Heat Capacity of the Rb3LnCl6 Compounds with Ln = La, Ce, Pr, Nd

1999 ◽  
Vol 54 (6-7) ◽  
pp. 397-403 ◽  
Author(s):  
L. Rycerz ◽  
M. Gaune-Escard
Keyword(s):  
Experimental Data ◽  
Phase Transition ◽  
Differential Scanning Calorimetry ◽  
Heat Capacity ◽  
Liquid Phase ◽  
Formation Enthalpy ◽  
Heat Capacities ◽  
Small Decrease ◽  
Scanning Calorimetry ◽  
Increasing Temperature

Abstract The heat capacities of the solid and liquid Rb3LnCl6 compounds, where Ln = La, Ce, Pr, Nd, have been determined by differential scanning calorimetry (DSC) in the temperature range 300 -1100 K. The heat capacity shows a small decrease with increasing temperature from the temperature of phase transition up to 150 -200 K above this transition for the Rb3CeCl6, Rb3PrCl6 and Rb3NdCl6 compounds. The measured heat capacities were used to calculate the formation enthalpy of the liquid phase. The results obtained compare satisfactorily with the known experimental data.

Heat Capacity of K3LnCl6 Compounds with Ln = La, Ce, Pr, Nd

1999 ◽  
Vol 54 (3-4) ◽  
pp. 229-235 ◽  
Author(s):  
M. Gaune-Escard ◽  
L. Rycerz
Keyword(s):  
Experimental Data ◽  
Phase Transition ◽  
Differential Scanning Calorimetry ◽  
Heat Capacity ◽  
Phase Transitions ◽  
Liquid Phase ◽  
Temperature Dependence ◽  
Heat Capacities ◽  
Scanning Calorimetry ◽  
The Enthalpy Of Formation

The heat capacities of the solid and liquid K3LnCl6 compounds (Ln = La, Ce, Pr, Nd) have been determined by differential scanning calorimetry (DSC) in the temperature range 300 -1100 K. Their temperature dependence is discussed in terms of the phase transitions of these compounds as reported in literature. The heat capacity increases and decreases strongly in the vicinity of a phase transition but else varies smoothly. The Cp data were fitted by an equation which provides a satisfactory representation up to the temperatures of Cp discontinuity. The measured heat capacities were checked for consistency by calculating the enthalpy of formation of the liquid phase, which had been previously measured. The results obtained compare satisfactorily with these experimental data.

scholarly journals Thermal Analysis of Binary Mixtures of Imidazolium, Pyridinium, Pyrrolidinium, and Piperidinium Ionic Liquids

Molecules ◽  
2021 ◽  
Vol 26 (21) ◽  
pp. 6383
Author(s):  
Elena Gómez ◽  
Pedro Velho ◽  
Ángeles Domínguez ◽  
Eugénia A. Macedo
Keyword(s):  
Thermal Analysis ◽  
Differential Scanning Calorimetry ◽  
Heat Capacity ◽  
Ionic Liquids ◽  
Thermal Behavior ◽  
Binary Mixtures ◽  
Heat Capacities ◽  
Viable Alternative ◽  
Transition Temperatures ◽  
Scanning Calorimetry

Ionic liquids (ILs) are being widely studied due to their unique properties, which make them potential candidates for conventional solvents. To study whether binary mixtures of pure ionic liquids provide a viable alternative to pure ionic liquids for different applications, in this work, the thermal analysis and molar heat capacities of five equimolar binary mixtures of ionic liquids based on imidazolium, pyridinium, pyrrolidinium, and piperidinium cations with dicyanamide, trifluoromethanesulfonate, and bis(trifluoromethylsulfonyl)imide anions have been performed. Furthermore, two pure ionic liquids based on piperidinium cation have been thermally characterized and the heat capacity of one of them has been measured. The determination and evaluation of both the transition temperatures and the molar heat capacities was carried out using differential scanning calorimetry (DSC). It was observed that the thermal behavior of the mixtures was completely different than the thermal behavior of the pure ionic liquids present, while the molar heat capacities of the binary mixtures were very similar to the value of the average of molar heat capacities of the two pure ionic liquids.

scholarly journals Heat capacity and thermal expansion of yttrium tantalate

2019 ◽  
Vol 484 (2) ◽  
pp. 181-183
Author(s):  
A. V. Khoroshilov ◽  
A. A. Ashmarin ◽  
V. N. Guskov ◽  
E. G. Sazonov ◽  
K. S. Gavrichev ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Heat Capacity ◽  
Thermal Expansion ◽  
Heat Capacities ◽  
Unit Cell ◽  
Unit Cell Parameters ◽  
Scanning Calorimetry ◽  
Crystal Lattices ◽  
Cell Parameters ◽  
The Difference

The isobaric heat capacities of two monoclinic (M' and M) modifications of yttrium orthotantalate at temperatures 5–1300 K have been measured by the adiabatic and differential scanning calorimetry methods. It has been demonstrated that the difference in structure between the crystal lattices of M' and M has small effect in the heat capacity, and the difference between the heat capacities of these phases Cp(M)-Cp(M') is small, always positive, and increases in the range of the lowest temperatures. The unit cell parameters of M-YTaO4 have been determined as a function of temperature in the range 300–1173 K.

An Evaluation of a Plasma Fractionation System

1960 ◽  
Vol 4 (01) ◽  
pp. 031-044
Author(s):  
George Y. Shinowara ◽  
E. Mary Ruth
Keyword(s):  
Biological Activity ◽  
Ionic Strength ◽  
Plasma Proteins ◽  
High Concentration ◽  
Significant Evidence ◽  
Native Proteins ◽  
Mobility Data ◽  
Fractionation Procedure ◽  
The Individual ◽  
Low Ionic Strength

SummaryFour primary fractions comprising at least 97 per cent of the plasma proteins have been critically appraised for evidence of denaturation arising from a low temperature—low ionic strength fractionation system. The results in addition to those referable to the recovery of mass and biological activity include the following: The high solubilities of these fractions at pH 7.3 and low ionic strengths; the compatibility of the electrophoretic and ultracentrifugal data of the individual fractions with those of the original plasma; and the recovery of hemoglobin, not hematin, in fraction III obtained from specimens contaminated with this pigment. However, the most significant evidence for minimum alterations of native proteins was that the S20, w and the electrophoretic mobility data on the physically recombined fractions were identical to those found on whole plasma.The fractionation procedure examined here quantitatively isolates fibrinogen, prothrombin and antithrombin in primary fractions. Results have been obtained demonstrating its significance in other biological systems. These include the following: The finding of 5 S20, w classes in the 4 primary fractions; the occurrence of more than 90 per cent of the plasma gamma globulins in fraction III; the 98 per cent pure albumin in fraction IV; and, finally, the high concentration of beta lipoproteins in fraction II.

Heat capacities and enthalpies of fusion and transformation for solvates of some salts with dimethyl sulfoxide and dimethylformamide

1988 ◽  
Vol 53 (12) ◽  
pp. 3072-3079
Author(s):  
Mojmír Skokánek ◽  
Ivo Sláma
Keyword(s):  
Heat Capacity ◽  
Phase Transformation ◽  
Phase Transformations ◽  
Dimethyl Sulfoxide ◽  
Liquidus Temperature ◽  
Molar Heat Capacity ◽  
Solid Phase ◽  
Zinc Nitrate ◽  
Heat Capacities ◽  
Liquid Phases

Molar heat capacities and molar enthalpies of fusion of the solvates Zn(NO3)2 . 2·24 DMSO, Zn(NO3)2 . 8·11 DMSO, Zn(NO3)2 . 6 DMSO, NaNO3 . 2·85 DMSO, and AgNO3 . DMF, where DMSO is dimethyl sulfoxide and DMF is dimethylformamide, have been determined over the temperature range 240 to 400 K. Endothermic peaks found for the zinc nitrate solvates below the liquidus temperature have been ascribed to solid phase transformations. The molar enthalpies of the solid phase transformations are close to 5 kJ mol-1 for all zinc nitrate solvates investigated. The dependence of the molar heat capacity on the temperature outside the phase transformation region can be described by a linear equation for both the solid and liquid phases.

scholarly journals Characteristics of Reconstituted Collagen Fibers from Chicken Keel Cartilage Depends on Salt Type for Removal of Proteoglycans

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3538
Author(s):  
Anna Pudło ◽  
Szymon Juchniewicz ◽  
Wiesław Kopeć
Keyword(s):  
Electron Microscopy ◽  
Rheological Properties ◽  
Thermal Denaturation ◽  
Surface Structures ◽  
Scanning Calorimetry ◽  
Cartilage Extracellular Matrix ◽  
Oscillatory Rheometry ◽  
Freeze Dried ◽  
Basic Features ◽  
Scanning Electron

The aim of the presented research was to obtain reconstituted atelocollagen fibers after extraction from poultry cartilage using the pepsin-acidic method in order to remove telopeptides from the tropocollagen. Firstly, we examined the extraction of collagen from the cartilage extracellular matrix (ECM) after proteoglycans (PG) had been removed by the action of salts, i.e., NaCl or chaotropic MgCl2. Additionally, the effects of the salt type used for PG and hyaluronic acid removal on the properties of self-assembled fibers in solutions at pH 7.4 and freeze-dried matrices were investigated. The basic features of the obtained fibers were characterized, including thermal properties using scanning calorimetry, rheological properties using dynamic oscillatory rheometry, and the structure by scanning electron microscopy. The fibers obtained after PG removal with both analyzed types of salts had similar thermal denaturation characteristics. However, the fibers after PG removal with NaCl, in contrast to those obtained after MgCl2 treatment, showed different rheological properties during gelatinization and smaller diameter size. Moreover, the degree of fibrillogenesis of collagens after NaCl treatment was complete compared to that with MgCl2, which was only partial (70%). The structures of fibers after lyophilization were fundamentally different. The matrices obtained after NaCl pretreatment form regular scaffolds in contrast to the thin, surface structures of the cartilage matrix after proteoglycans removal using MgCl2.

scholarly journals DESIGN, OPTIMIZATION AND EVALUATION OF CETRIZINE DIHYDROCHLORIDE FAST DISSOLVING FILMS EMPLOYING STARCH TARTRATE–A NOVEL SUPERDISINTEGRANT

2019 ◽  
pp. 75-86
Author(s):  
R. SANTOSH KUMAR ◽  
ANNU KUMARI ◽  
B. KUSUMA LATHA ◽  
PRUDHVI RAJ
Keyword(s):  
Tensile Strength ◽  
Drug Dissolution ◽  
In Vitro Dissolution ◽  
Content Uniformity ◽  
Scanning Calorimetry ◽  
Disintegration Time ◽  
Folding Endurance ◽  
Contour Plots ◽  
The Individual

Objective: The aim of the current research is optimization, preparation and evaluation of starch tartrate (novel super disintegrant) and preparation of fast dissolving oral films of cetirizine dihydrochloride by employing starch tartrate. Methods: To check the drug excipient compatibility studies of the selected drug (Cetrizine dihydrochloride) and the prepared excipient i. e starch tartrate, different studies like FTIR (Fourier-transform infrared spectroscopy), DSC (Differential scanning calorimetry) and thin-layer chromatography (TLC) were carried out to find out whether there is any interaction between cetirizine dihydrochloride and starch tartrate. The solvent casting method was used for the preparation of fast dissolving films. The prepared films were then evaluated for thickness, folding endurance, content uniformity, tensile strength, percent elongation, in vitro disintegration time and in-vitro dissolution studies. Response surface plots and contour plots were also plotted to know the individual and combined effect of starch tartrate (A), croscarmellose sodium (B) and crospovidone (C) on disintegration time and drug dissolution efficiency in 10 min (dependent variables). Results: Films of all the formulations are of good quality, smooth and elegant by appearance. Drug content (100±5%), thickness (0.059 mm to 0.061 mm), the weight of films varies from 51.33 to 58.06 mg, folding endurance (52 to 67 times), tensile strength (10.25 to 12.08 N/mm2). Fast dissolving films were found to disintegrate between 34 to 69 sec. Percent dissolved in 5 min were found to be more in F1 formulation which confirms that starch tartrate was effective at 1%. Conclusion: From the research conducted, it was proved that starch tartrate can be used in the formulation of fast dissolving films of cetirizine dihydrochloride. The disintegration time of the films was increased with increase in concentration of super disintegrant.

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