Thermodynamic properties of peptide solutions. The relative partial molar enthalpies of aqueous solutions of glycylglycylglycine, glycylglycylalanine and alanylglycylglycine

1983 ◽  
Vol 36 (9) ◽  
pp. 1813 ◽  
Author(s):  
MK Kumaran ◽  
ID Watson ◽  
GR Hedwig

The enthalpies of dilution at 298 K of aqueous solutions of the tripeptides glycylglycylglycine, glycylglycylalanine and alanylglycylglycine have been determined by flow microcalorimetry. From these data the partial molar enthalpies of the solvent in the solutions have been calculated. The results indicate that water side-chain interactions make an important contribution to the solvation of peptides.

2016 ◽  
Vol 113 (30) ◽  
pp. 8424-8429 ◽  
Author(s):  
Yangzhong Qin ◽  
Lijuan Wang ◽  
Dongping Zhong

Protein hydration is essential to its structure, dynamics, and function, but water–protein interactions have not been directly observed in real time at physiological temperature to our awareness. By using a tryptophan scan with femtosecond spectroscopy, we simultaneously measured the hydration water dynamics and protein side-chain motions with temperature dependence. We observed the heterogeneous hydration dynamics around the global protein surface with two types of coupled motions, collective water/side-chain reorientation in a few picoseconds and cooperative water/side-chain restructuring in tens of picoseconds. The ultrafast dynamics in hundreds of femtoseconds is from the outer-layer, bulk-type mobile water molecules in the hydration shell. We also found that the hydration water dynamics are always faster than protein side-chain relaxations but with the same energy barriers, indicating hydration shell fluctuations driving protein side-chain motions on the picosecond time scales and thus elucidating their ultimate relationship.


Author(s):  
O.V. Kalashnikov ◽  
S.V. Budniak ◽  
Yu.V. Ivanov ◽  
Yu.M. Belyansky ◽  
N.O. Aptulina ◽  
...  

The experimental and calculated according to program systems GasCondOil, Aspen-HYSYS and PRO-II compositions of the gas — liquid phases (hydrocarbon and aqueous solutions) and their thermodynamic properties are compared, as well as the accuracy of technological calculations of field pipelines and natural gas and oil treatment processes. It is shown that some of the field technological processes, calculated by the program system GasCondOil, are not modeled on Aspen-HYSYS. Bibl. 16, Fig. 9, Tab. 15.


2015 ◽  
Vol 1092-1093 ◽  
pp. 1455-1459
Author(s):  
Chu Yue Hou ◽  
Gui Ying Zhou ◽  
Jian Kang Wen ◽  
Biao Wu

In this paper, we jointly use the Pitzer model and the Meissner model to study thermodynamic laws of bioleaching solution in a lean nickel-cobalt ore in the Jilin Baishan, by using the Pitzer model to calculate activity coefficients of single electrolyte aqueous solutions and the Meissner model to calculate activity coefficients of components in the bioleaching solution. Also we studied the rules of activity coefficient of NiSO4 and CoSO4 in the solution. Results show that when separating and purifying foreign ions from bioleaching solution of the lean nickel-cobalt ore, the descending sequence of their ion concentration’s effect over the solution is Mg2+, Fe3+, Fe2+, Ni2+, Co2+ and Ca2+.


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