scholarly journals Ion Complexation Explains Orders of Magnitude Changes in the Equilibrium Constant of Biochemical Reactions in Buffers Crowded by Nonionic Compounds

Author(s):  
Krzysztof Bielec ◽  
Adam Kowalski ◽  
Grzegorz Bubak ◽  
Emilia Witkowska Nery ◽  
Robert Hołyst
2015 ◽  
Vol 60 (3) ◽  
pp. 263-267
Author(s):  
L.A. Bulavin ◽  
◽  
S.V. Khrapatyi ◽  
V.M. Makhlaichuk ◽  

Author(s):  
A.V. Shitikova ◽  
◽  
A.A. Abiala

The results of studies on the role of growth biostimulants in the exogenous regulation of potato productivity on sod-podzolic soils of the Moscow region are presented.Studies have established the specificity of the action of phytohormones.The stimulating effect of the drugs manifested itself in the intensification of metabolic processes, changing the direction of biochemical reactions, which led to an increase in productivity.


2000 ◽  
Author(s):  
Jerald S. Bradshaw ◽  
Guoping Xue ◽  
Xian X. Zhang ◽  
Paul B. Savage ◽  
Krzysztof E. Krakowiak

2000 ◽  
Vol 42 (3-4) ◽  
pp. 265-272 ◽  
Author(s):  
T. Inoue ◽  
Y. Nakamura ◽  
Y. Adachi

A dynamic model, which predicts non-steady variations in the sediment oxygen demand (SOD) and phosphate release rate, has been designed. This theoretical model consists of three diffusion equations with biochemical reactions for dissolved oxygen (DO), phosphate and ferrous iron. According to this model, step changes in the DO concentration and flow velocity produce drastic changes in the SOD and phosphate release rate within 10 minutes. The vigorous response of the SOD and phosphate release rate is caused by the difference in the time scale of diffusion in the water boundary layer and that of the biochemical reactions in the sediment. Secondly, a negative phosphate transfer from water to sediment can even occur under aerobic conditions. This is caused by the decrease in phosphate concentration in the aerobic layer due to adsorption.


1985 ◽  
Vol 50 (8) ◽  
pp. 1648-1660 ◽  
Author(s):  
Ernest Beinrohr ◽  
Andrej Staško ◽  
Ján Garaj

The oxidation of nickel(II) bis(diethyldithiocarbamate) (NiL2) by N,N,N',N'-tetraethyl thiuramdisulphide (tds) can be described by the equation 2 NiL2 + tds ⇄ 2 NiL3 (NiL3 = tris(diethyldithiocarbamate) nickel(III)). The equilibrium constant of the reaction depends on the polarity of the solvent (4.4 . 10-3 in toluene, 1.3 . 10-3 in chloroform, and 8 . 10-4 in acetone and methanol). The rate constants k1 and k-2 and the ratio k2/k-1 were found for the reaction steps NiL2 + tds ⇄ NiL3 + L. and NiL2 + L. ⇄ NiL3, where L. is the (C2H5)2NCS2. radical.


1981 ◽  
Vol 46 (2) ◽  
pp. 452-456
Author(s):  
Milan Šolc

The successive time derivatives of relative entropy and entropy production for a system with a reversible first-order reaction alternate in sign. It is proved that the relative entropy for reactions with an equilibrium constant smaller than or equal to one is completely monotonic in the whole definition interval, and for reactions with an equilibrium constant larger than one this function is completely monotonic at the beginning of the reaction and near to equilibrium.


1989 ◽  
Vol 54 (2) ◽  
pp. 440-445 ◽  
Author(s):  
Vladimír Macháček ◽  
Alexandr Čegan ◽  
Miloš Sedlák ◽  
Vojeslav Štěrba

The intramolecular nucleophilic addition of N-methyl-N-(2,4,6-trinitrophenyl)glycine anion in methanol-dimethyl sulfoxide mixtures produces spiro[(3-methyl-5-oxazolidinone)-2,1'-(2',4',6'-trinitrobenzenide)]. The spiro adduct has been identified by means of 1H and 13C NMR spectroscopy. This is the first case when the formation of a Meisenheimer adduct with carboxylate ion is observed. Logarithm of the equilibrium constant of adduct formation increases linearly with the mole fraction of dimethyl sulfoxide in its mixture with methanol.


Author(s):  
Dennis Sherwood ◽  
Paul Dalby

Building on the previous chapter, this chapter examines gas phase chemical equilibrium, and the equilibrium constant. This chapter takes a rigorous, yet very clear, ‘first principles’ approach, expressing the total Gibbs free energy of a reaction mixture at any time as the sum of the instantaneous Gibbs free energies of each component, as expressed in terms of the extent-of-reaction. The equilibrium reaction mixture is then defined as the point at which the total system Gibbs free energy is a minimum, from which concepts such as the equilibrium constant emerge. The chapter also explores the temperature dependence of equilibrium, this being one example of Le Chatelier’s principle. Finally, the chapter links thermodynamics to chemical kinetics by showing how the equilibrium constant is the ratio of the forward and backward rate constants. We also introduce the Arrhenius equation, closing with a discussion of the overall effect of temperature on chemical equilibrium.


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