scholarly journals Uncovering the Relationship between the Change in Heat Capacity for Enzyme Catalysis and Vibrational Frequency through Isotope Effect Studies

ACS Catalysis ◽  
2018 ◽  
Vol 8 (6) ◽  
pp. 5340-5349 ◽  
Author(s):  
Hannah B. L. Jones ◽  
Rory M. Crean ◽  
Christopher Matthews ◽  
Anna B. Troya ◽  
Michael J. Danson ◽  
...  
Keyword(s):  
Heat Capacity ◽  
Isotope Effect ◽  
Enzyme Catalysis ◽  
Vibrational Frequency ◽  
The Relationship

scholarly journals Change in Heat Capacity for Enzyme Catalysis Determines Temperature Dependence of Enzyme Catalyzed Rates

2017 ◽  
Vol 12 (3) ◽  
pp. 868-868 ◽  
Author(s):  
Joanne K. Hobbs ◽  
Wanting Jiao ◽  
Ashley D. Easter ◽  
Emily J. Parker ◽  
Louis A. Schipper ◽  
...  
Keyword(s):  
Heat Capacity ◽  
Temperature Dependence ◽  
Enzyme Catalysis

scholarly journals On the relationship between folding and chemical landscapes in enzyme catalysis

2008 ◽  
Vol 105 (37) ◽  
pp. 13877-13882 ◽  
Author(s):  
M. Roca ◽  
B. Messer ◽  
D. Hilvert ◽  
A. Warshel
Keyword(s):  
Enzyme Catalysis ◽  
The Relationship

Studies in Solvolysis. Part VII. The Neutral Hydrolysis of Methyl Perchlorate

1975 ◽  
Vol 53 (20) ◽  
pp. 3106-3115 ◽  
Author(s):  
Ross Elmore Robertson ◽  
Adrianna Annesa ◽  
John Marshall William Scott
Keyword(s):  
Heat Capacity ◽  
Carbon Atom ◽  
Temperature Dependence ◽  
Thermodynamic Parameters ◽  
Isotope Effect ◽  
Perchlorate Ion ◽  
Rate Of Hydrolysis ◽  
Leaving Groups ◽  
Hydrolysis Of

The temperature dependence of the rate of hydrolysis of methyl perchlorate has been measured and the entropy (ΔS≠), enthalpy (ΔH≠), and heat capacity (ΔCp≠) of activation calculated. The measurements confirm that the perchlorate ion is superior to all other leaving groups in water. The isotope effect related to the hydrolysis of methyl-d3 perchlorate has been measured at three temperatures and shown to be inverse. The thermodynamic parameters and the isotope effect were examined with respect to the mechanism of substitution at a primary carbon atom.

A Study of Na2O-TiO2-SiO2 Glasses by Infrared Spectroscopy

1974 ◽  
Vol 28 (3) ◽  
pp. 256-259 ◽  
Author(s):  
Murli H. Manghnani ◽  
John R. Ferraro ◽  
L. J. Basile
Keyword(s):  
Infrared Spectroscopy ◽  
Absorption Band ◽  
Infrared Absorption ◽  
Vibrational Frequency ◽  
Silicate Glasses ◽  
Molar Ratio ◽  
Frequency Range ◽  
Weak Absorption ◽  
Infrared Absorption Spectra ◽  
The Relationship

The infrared absorption spectra of six Na2O-TiO2-SiO2 glasses in the frequency range of 1600 to 200 cm−1 are reported. These glasses, having a SiO2/Na2O molar ratio of 1.07 to 3.54, and containing 20 or 25 mole % TiO2, demonstrate two main absorptions at ∼950 cm−1 and at ∼450 cm−1. A weak absorption at ∼790 cm−1 becomes progressively weaker in intensity, and a weak shoulder at 1050 cm−1 appears with increasing Na2O content. The frequency of the absorption band at ∼950 cm−1 is found to decrease markedly and systematically with a decrease in the SiO2/Na2O molar ratio, whereas the frequency of the band at ∼450cm−1 shows a slight increase. The infrared results may be interpreted in terms of a lowering of symmetry occurring for the SiO4 units. The effect of TiO2 content on the relationship between vibrational frequency is discussed. The frequency composition curves for glasses containing 20 and 25 mole % of TiO2 intersect at SiO2/Na2O ratio ∼2. A reversal in the frequency vs SiO2/Na2O ratio relation was also found at SiO2/Na2O ∼2 for the sodium silicate glasses.

First-Principles Calculations of Elastic and Thermodynamic Properties of Cubic CdTe

2011 ◽  
Vol 268-270 ◽  
pp. 886-891
Author(s):  
Ben Hai Yu ◽  
Dong Chen
Keyword(s):  
Experimental Data ◽  
Heat Capacity ◽  
Thermodynamic Properties ◽  
Bulk Modulus ◽  
First Principles ◽  
Debye Model ◽  
First Principles Calculations ◽  
Lattice Constants ◽  
Temperature And Pressure ◽  
The Relationship

the equilibrium lattice constants, elastic and thermodynamic properties of cubic CdTe are systemically investigated at high temperature using the plane-wave pseudopotential method as well as the quasi-harmonic Debye model. The bulk modulus of CdTe are calculated as a function of temperature up to 1000K, the relationship between bulk modulusBand pressure is also obtained. The results gained from this model will provide overall predictions accurately for the temperature and pressure dependence of various quantities such as the bulk modulus, the heat capacity and the thermal expansion coefficient. More over, the dependences between Debye temperature and temperature are also successfully obtained. Our results are compared with the experimental data and discussed in light of previous works.

scholarly journals The Triple Product Rule is Incorrect

2021 ◽  
Vol 1 (2) ◽  
pp. 1-3
Author(s):  
Igor Stepanov*
Keyword(s):  
Heat Capacity ◽  
Thermal Expansion ◽  
Isothermal Compressibility ◽  
Chain Rule ◽  
Triple Product ◽  
Product Rule ◽  
Capacity Ratio ◽  
The Difference ◽  
The Relationship ◽  
Derivatives Of

The triple product rule, also known as the cyclic chain rule, cyclic relation, cyclical rule or Euler's chain rule, relates the partial derivatives of three interdependent variables, and often finds application in thermodynamics. It is shown here that its derivation is wrong, and that this rule is not correct; hence, the Mayer's relation and the heat capacity ratio, which describe the difference between isobaric and isochoric heat capacities, are also untrue. Also, the relationship linking thermal expansion and isothermal compressibility is wrong. These results are confirmed by many experiments and by the previous theoretical findings of the author.

Nano-second protein dynamics of key residue at Position 38 in catechol-O-methyltransferase system: a time-resolved fluorescence study

2020 ◽  
Vol 168 (4) ◽  
pp. 417-425
Author(s):  
Fan Liu ◽  
Jianyu Zhang
Keyword(s):  
Protein Dynamics ◽  
Enzyme Catalysis ◽  
Time Resolved Fluorescence ◽  
Fluorescence Study ◽  
Time Resolved ◽  
System A ◽  
Key Enzyme ◽  
Relationship Of ◽  
The Relationship ◽  
Stokes Shifts

Abstract Human catechol-O-methyltransferase, a key enzyme related to neurotransmitter metabolism, catalyses a methyl transfer from S-adenosylmethionine to catechol. Although extensive studies aim to understand the enzyme mechanisms, the connection of protein dynamics and enzyme catalysis is still not clear. Here, W38in (Trp143Phe) and W38in/Y68A (Trp143Phe with Tyr68Ala) mutants were carried out to study the relationship of dynamics and catalysis in nano-second timescale using time-resolved fluorescence lifetimes and Stokes shifts in various solvents. The comprehensive data implied the mutant W38in/Y68A with lower activity is more rigid than the ‘WT’−W38in, suggesting the importance of flexibility at residue 38 to maintain the optimal catalysis.

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