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Abstract  

After a formal explanation of Mayer's enthalpy balance method as applied to biological reaction rates, the history of its application is traced from Rubner's dog to accounting for the energy of muscle contraction. The introduction of microcalorimetry allowed the method generally to be used for cells in vitro and now particular emphasis can be paid to the growth of cells for the production of therapeutically-important heterologous proteins. In these systems, enthalpy balance studies contribute to defining catabolic processes, designing media, understanding the mechanisms of growth and controlling cultures using heat flux as an on-line sensor of metabolic activity.

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Introduction In the discussion on thermokinetic analysis of reaction/process of thermal decomposition of compounds undergoing destruction with observable weight loss: 1 (where the stoichiometric coefficient ν is sum of

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Abstract  

Microcalorimetric titrations allow to recognize and investigate high-affinity ligand binding to Na,K-ATPase. Titrations with the cardiac glycoside Ouabain, which acts as a specific inhibitor of the enzyme, have provided not only the thermodynamic parameters of high-affinity binding with a stoichiometric coefficient of about 0.6 but also evidence for low-affinity binding to the lipid. The marked enthalpic contribution of -95 kJ mol-1 at 298.2 K is partially compensated by a large negative entropy change, attributed to an increased interaction between water and the protein. The calorimetric ADP and ATP titrations at 298.2 K are indicative of high-affinity nucleotide binding either in 3 mM NaCl, 3 mM MgCl2 or at high ionic strength such as 120 mM choline chloride. However, no binding is detected in the buffer solution alone at low ionic strength. The affinities for ADP and ATP are similar, around 106 M-1 and the stoichiometric coefficients are close to that of Ouabain binding. The exothermic binding of ADP is characterized by a ΔH and ΔS value of -65 kJ mol-1 and -100 J mol-1 K-1, respectively. TheΔH value for ATP binding is larger than for ADP and is compensated by a larger, unfavorable ΔS value. This leads to an enthalpy/entropy compensation, which could express that H-bond formation represents the major type of interaction. As for Ouabain, the negative ΔS values that are also characteristic of nucleotide binding can indicate an increase of solvate interaction with the protein due to a conformational transition occurring subsequent to the binding process. The resulting binding constants are discussed with regard to the results of other studies employing different techniques. A molecular interaction model for nucleotide binding is suggested.

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Abstract  

For the assessment of the analytical error of concentration dependent distribution (CDD), complex-forming separation reaction was proposed in a generalized form of equilibrium
\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $$ML_{< n > } + + nL \rightleftarrows \overline {ML} _{< \bar n > }$$ \end{document}
, where n is the effective stoichiometric coefficient, i.e. the difference of mean ligand numbers
\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $$< \bar n >$$ \end{document}
and <n> of a mixture of complexes of analyte M with reagent L in the respective groups (distinguished by bars above the symbols) of the separation system. Calibration curve
\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $$I = A/\bar A$$ \end{document}
is derived from measurement of gross activity of complexes, A=A(ML<n>) and
\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $$\bar A = A(\overline {ML} _{< \bar n > } )$$ \end{document}
. Theoretical relative error is expressed as a product of three terms,
\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $$\bar R$$ \end{document}
) vs. the analyte; reagent ratio, n(Z+1)/T. The form of slope is analyzed on the basis of the generalized separation reaction. Optimal conditions were discussed from this point of view and the ideal case is at f2=1. The third term f3 depends on the activities A and
\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $$\bar R$$ \end{document}
(0.2;0.8) is suggested
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ν A stoichiometric coefficient of compound A mc p /J K −1 heat capacity of the whole system (reaction mixture and reactor

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Journal of Thermal Analysis and Calorimetry
Authors: Isabel Galan, Carmen Andrade, and Marta Castellote

the same temperature range as the C–S–H gel water and which interact as well with the CO 2 , are not considered. Figure 13 represents the values of the CaO stoichiometric coefficient in the C–S–H after 1 year, y . The numbers

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. ( 3 ) takes a form: 5 When ν = ν i and Σ ν i = ν i and in consequence φ = 1, relation ( 5 ) has a very simple form [ 2 ]: 6 For reactions in which more than one gaseous product is released ratio of stoichiometric coefficients φ has to

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listed in Table 1 together with the corresponding stoichiometric coefficients. Table 1 Elementary steps and their stoichiometric coefficients involved in the reaction paths considered

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are stoichiometric coefficients, and G is the guest component (organic or inorganic compound [ 6 , 7 ]). Similar to graphite [ 8 – 10 ], depending on equilibrium conditions and the guest component nature, fluorographite matrices may form inclusion

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obtain the following general expression for the reaction rate of the step i for the consecutive reaction scheme, Eq. 18 : 23 where X i ∞ is calculated from the stoichiometric coefficients according to the following expression: 24 TG data

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