Gibbs energies, enthalpies, and entropies of water and lysozyme at the inner edge of excess hydration

The aim of this study is to simultaneously monitor the excess partial Gibbs energies, enthalpies, and entropies of water and white egg lysozyme and demonstrate how these quantities correlate with the coverage of the protein macromolecules by water molecules. Isothermal calorimetry and water sorption measurements were applied to characterize the hydration dependencies of the excess thermodynamic functions. The excess partial quantities are found to be sensitive to changes in the water and protein states. At the lowest water weight fractions (w1), changes in the excess functions are primarily attributable to the addition of water. The transition of lysozyme from a glassy (rigid) to a flexible (elastic) state is accompanied by significant changes in the excess partial quantities. When the charged groups on the protein are covered, this transition occurs at w1 = 0.05; when the coverage of both polar and weakly interacting surface elements is complete, the excess partial quantities become hydrated at w1 > 0.5. At the highest water content, water addition has no significant effect on the excess quantities. At w1 > 0.5, changes in the excess functions solely reflect changes in the state of the protein. © 2013 AIP Publishing LLC

A study of the hydration of ribonuclease A using isothermal calorimetry: Effect of the protein hydrophobicity and polarity

© 2014 Akadémiai Kiadó, Budapest, Hungary. This work is part of a systematic study undertaken to find the excess thermodynamic functions of binary protein-water systems. Isothermal calorimetry and water sorption measurements were applied to characterize the hydration dependencies of the excess thermodynamic functions. The advantages of our methodology are (i) we are able to simultaneously determine the excess partial quantities of water and proteins; (ii) these thermodynamic quantities can be determined in the entire range of water content. Here, in particular, the excess partial enthalpies of water and bovine pancreatic ribonuclease A (RNase A) have been determined. The excess partial enthalpies for RNase A are compared with the published data for several unrelated globular proteins (lysozyme, chymotrypsinogen A, serum albumin, lactoglobulin). These biomacromolecules represent a series of proteins in which the hydrophobicity of proteins is gradually changed in a wide range. It was found that the excess partial quantities for the studied proteins are determined by the hydration of the hydrophilic and hydrophobic protein groups. The more hydrophilic a protein, the more significant a hydrophilic hydration contribution is and vice versa. RNase A is the most hydrophilic protein under the study. This protein has the most significant hydrophilic hydration contribution. Lactoglobulin is the most hydrophobic protein under the study. This protein has the most significant hydrophobic hydration contribution

Hydration of α-chymotrypsin: Excess partial enthalpies of water and enzyme

A novel method has been developed for studying simultaneously the excess partial enthalpies of water and the enzyme in the entire range of water content. Bovine pancreatic α-chymotrypsin was used as a model enzyme. The proposed method includes the measurements of the enthalpies of solution of the dried and hydrated enzyme in water at 25 °C. From these thermochemical data the excess partial enthalpies of water and α-chymotrypsin were calculated. The partial quantities are very sensitive to the changes in the state of water and α-chymotrypsin. A transition from the glassy to the flexible state of α-chymotrypsin is accompanied by significant changes in the excess partial enthalpies of water and α-chymotrypsin. This transition appears at water weight fraction (w1) of 0.06 when charged groups of α-chymotrypsin are covered. Excess partial quantities reach their fully hydrated values at w1 > 0.4 when coverage of both polar and weakly interacting surface elements is complete. © 2011 Elsevier B.V. All rights reserved

A study of the excess gibbs energy of ribonuclease a - water mixtures

© 2014 by Nova Science Publishers, Inc. All rights reserved. Water sorption measurements were applied to characterize the hydration dependencies of the excess thermodynamic functions of binary protein-water mixtures. The aim of this study is to demonstrate how these quantities correlate with the coverage of the protein macromolecules by water molecules. The advantages of our methodology are (i) we are able to simultaneously determine the excess partial quantities of water and proteins; (ii) these thermodynamic quantities can be determined in the entire range of water content. Here, in particular, the excess Gibbs energies of the binary system of bovine pancreatic ribonuclease A (RNase A) with water were obtained as a function of composition at 25 °C. The results from the thermodynamic measurements were analysed to give a unified picture of the hydration process of proteins

Analysis of hydration of ovalbumin by densitometry

© 2014 by Nova Science Publishers, Inc. All rights reserved. High-precision densitometry was applied to study the hydration of hen egg-white ovalbumin. The excess volumes of the binary system of ovalbumin with water were obtained as a function of composition at 25 °C. The hydration process was characterised by analysing the excess functions of mixing. This method facilitates the individual evaluation of the protein and water partial quantities in the entire range of water content. The excess partial volumes are extremely sensitive to changes in the state of water and the protein. The excess volumes are determined by the hydration of the hydrophilic and hydrophobic protein groups. It was found that the more hydrophilic a protein is, the more significant the hydrophilic hydration contribution is

Analysis of hydration of ovalbumin by isothermal calorimetry

© 2014 by Nova Science Publishers, Inc. All rights reserved. Isothermal calorimetry was applied to characterize the hydration dependencies of the excess thermodynamic functions of binary proteinwater systems. Here, in particular, the excess partial enthalpies of water and hen egg-white ovalbumin have been determined. The excess partial enthalpies for ovalbumin are compared with the published data for several unrelated globular proteins (ribonuclease A, lysozyme, chymotrypsinogen A, serum albumin, lactoglobulin). These biomacromolecules represent a series of proteins in which the hydrophobicity of proteins is gradually changed over a wide range. It was found that the excess partial quantities for the studied proteins are determined by the hydration of the hydrophilic and hydrophobic protein groups. The more hydrophilic a protein, the more significant a hydrophilic hydration contribution is and vice versa. Ribonuclease A is the most hydrophilic protein in the present study. This protein has the most significant hydrophilic hydration contribution. Lactoglobulin is the most hydrophobic protein under the study. This protein has the most significant hydrophobic hydration contribution. Ovalbumin shows intermediate properties

Hydration of proteins: Excess partial enthalpies of water and proteins

Isothermal batch calorimetry was applied to study the hydration of proteins. The hydration process was analyzed by the simultaneous monitoring of the excess partial enthalpies of water and the proteins in the entire range of water content. Four unrelated proteins (lysozyme, chymotrypsinogen A, human serum albumin, and β-lactoglobulin) were used as models. The excess partial quantities are very sensitive to the changes in the state of water and proteins. At the lowest water weight fractions (w1), the changes of the excess thermochemical functions can mainly be attributed to water addition. A transition from the glassy to the flexible state of the proteins is accompanied by significant changes in the excess partial quantities of water and the proteins. This transition appears at a water weight fraction of 0.06 when charged groups of proteins are covered. Excess partial quantities reach their fully hydrated values at w1 > 0.5 when coverage of both polar and weakly interacting surface elements is complete. At the highest water contents, water addition has no significant effect on the excess thermochemical quantities. At w1 > 0.5, changes in the excess functions can solely be attributed to changes in the state of the proteins. © 2011 American Chemical Society

A study of the hydration of ribonuclease A using densitometry: Effect of the protein hydrophobicity and polarity

The excess volumes of the binary system of ribonuclease A (RNase A) with water were obtained as a function of composition at 25 °C. The excess quantities for RNase A were compared with the published data for several unrelated proteins (lysozyme, serum albumin, lactoglobulin, and chymotrypsinogen A). The hydrophobicity of these proteins is gradually changed over a wide range. It was found that the more hydrophilic a protein is, the more significant the hydrophilic hydration contribution is. RNase A is the most hydrophilic protein in the present study, and it has the most significant hydrophilic hydration contribution. © 2014 Elsevier B.V. All rights reserved

Hydration of proteins: Excess partial volumes of water and proteins

High precision densitometry was applied to study the hydration of proteins. The hydration process was analyzed by the simultaneous monitoring of the excess partial volumes of water and the proteins in the entire range of water content. Five unrelated proteins (lysozyme, chymotrypsinogen A, ovalbumin, human serum albumin, and β-lactoglobulin) were used as models. The obtained data were compared with the excess partial enthalpies of water and the proteins. It was shown that the excess partial quantities are very sensitive to the changes in the state of water and proteins. At the lowest water weight fractions (w 1), the changes of the excess functions can mainly be attributed to water addition. A transition from the glassy to the flexible state of the proteins is accompanied by significant changes in the excess partial quantities of water and the proteins. This transition appears at a water weight fraction of 0.06 when charged groups of proteins are covered. Excess partial quantities reach their fully hydrated values at w1 > 0.5 when coverage of both polar and weakly interacting surface elements is complete. At the highest water contents, water addition has no significant effect on the excess quantities. At w1 > 0.5, changes in the excess functions can solely be attributed to changes in the state of the proteins. © 2012 American Chemical Society

Industrial paternalism as institutional trap (QWERTY- effects)

The article provides the theoretic-methodical approach to the particular qualities of the development and functioning of paternalism as a special management practices, based on a system of mutual expectations and actions on the part of management and employees of the industrial sector. The given approach takes the principles of behavioural economy as the basis and explains the necessity of methods of state regulation by the existence of institutional traps (QWERTY effects) and cognitive and behavioural anomalies corrected as a result of state implantation of the normative standard into the structure of subjective preferences of economic agents. The article provides rationalization for the necessity of application of measures of the direct influence limiting possibilities of an individual choice present at a high risk level of irrational behavior, and the measures of indirect influence correcting an individual choice of short-term benefit, interfaced with high expenses in the longterm period