The Thermodynamics of the Krebs Cycle and Related Compounds

Miller, Stanley L.; Smith-Magowan, David

doi:10.1063/1.555878

Cited by 75 publications

(64 citation statements)

References 42 publications

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“…We use Kapp rather than the thermodynamic Keg because we are interested in concentrations rather than thermodynamic activities. We will use the single ion activity coefficient approach in these calculations (Kielland, 1937;Miller and Smith-Magowan, 1990). For potassium ferrocyanide activity coefficients we have…”

Section: The Stability Of Ferrocyanidementioning

confidence: 99%

Was ferrocyanide a prebiotic reagent?

Keefe

Miller

1996

Origins Life Evol Biosphere

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Abstract.Hydrogen cyanide is the starting material for a diverse array of prebiotic syntheses, including those of amino acids and purines. Hydrogen cyanide also reacts with ferrous ions to give ferrocyanide, and so it is possible that ferrocyanide was common in the early ocean. This can only be true if the hydrogen cyanide concentration was high enough and the rate of reaction of cyanide with ferrous ions was fast enough. We show experimentally that the rate of formation of ferrocyanide is rapid even at low concentrations of hydrogen cyanide in the pH range 6-8, and therefore an equilibrium calculation is valid. The equilibrium concentrations of ferrocyanide are calculated as a function of hydrogen cyanide concentration, pH and temperature.The steady state concentration of hydrogen cyanide depends on the rate of synthesis by electric discharges and ultraviolet light and the rate of hydrolysis, which depends on pH and temperature. Our conclusions show that ferrocyanide was a major species in the prebiotic ocean only at the highest production rates of hydrogen cyanide in a strongly reducing atmosphere and at temperatures of 0 "C or less, although small amounts would have been present at lower hydrogen cyanide production rates. The prebiotic application of ferrocyanide as a source of hydrated electrons, as a photochemical replication process, and in semi-permeable membranes is discussed.

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Section: The Stability Of Ferrocyanidementioning

confidence: 99%

Was ferrocyanide a prebiotic reagent?

Keefe

Miller

1996

Origins Life Evol Biosphere

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“…The data [40] for the reaction: Since Reaction (25) describes equilibrium between hydrogen and NADH, the small value of generalized entropy change indicates that NADH is a reducing agent as effective as hydrogen. In many textbooks, ATP is introduced as an energy currency within the cell.…”

Section: Entropy Deficit Inherent In Atp and Nad(p)hmentioning

confidence: 99%

Scientific Élan Vital: Entropy Deficit or Inhomogeneity as a Unified Concept of Driving Forces of Life in Hierarchical Biosphere Driven by Photosynthesis

Sato

2012

Entropy

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Abstract:Life is considered something different from non-living things, but no single driving force can account for all the different aspects of life, which consists of different levels of hierarchy, such as metabolism, cell physiology, multi-cellular development and organization, population dynamics, ecosystem, and evolution. Although free energy is evidently the driving force in biochemical reactions, there is no established relationship between metabolic energy and spatiotemporal organization of living organisms, or between metabolic energy and genetic information. Since Schrödinger pointed out the importance of exporting entropy in maintaining life, misunderstandings of entropy notion have been obstacles in constructing a unified view on the driving forces of life. Here I present a simplified conceptual framework for unifying driving forces of life at various different levels of hierarchy. The key concept is "entropy deficit", or simply, 'inhomogeneity', which is defined as the difference of maximal possible entropy and actual entropy. This is equivalent to information content in genetic information and protein structure, and is also defined similarly for non-homogeneous structures in ecosystems and evolution. Entropy deficit or inhomogeneoity is a unified measure of all driving forces of life, which could be considered a scientific equivalent to 'élan vital' of Bergson.

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“…Therefore, Buckel and Miller, 1987 Assuming that the A,G"' of both stereoisomers is the same (Miller and Smith-Magowan, 1990).…”

Section: Assay Of Malease and Citraconase Activitymentioning

confidence: 99%

“…The relation in A,G"' for a racemic mixture and an optically pure compound is given by Eqn (8) (Miller and Smith-Magowan, 1990 The data presented by K h a and De& (1983) were corrected for the formation of optically pure malic acid (Eqn 8) and these corrected data for AGO' and AS"' are given in Table 3.…”

Section: Determination Of Ah"' and As"'mentioning

confidence: 99%

Thermodynamics of the maleate and citraconate hydration reactions catalysed by malease from Pseudomonas pseudoalcaligenes

Werf

Tweel

Hartmans

1993

European Journal of Biochemistry

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Malease from Pseudomonas pseudoalcaligenes catalyses the hydration of both maleate and citraconate to D-malate and D-citramalate, respectively. The K,,, for these hydration reactions were 2050 and 104, respectively, under standard biochemical conditions (25"C, pH 7.0, I = 0.1). The influence of the pH (6.0-8.5) on Kapp was determined. The Gibbs-free-energy changes under standard biochemical conditions for the hydration of the dianionic acids were calculated to be -19.28 kJ . mol-' and -11.65 kJ . mol-', respectively. From the obtained data together with data from the literature, the Gibbs free energy of formation of maleate*-and citraconate2-were calculated to be -588.91 kJ . mol-' and -600.56 kJ . mol-I, respectively. The influence of the temperature (10-40°C) on K,,, was determined for both hydration reactions. The enthalpy change (AH"') and entropy change (AS"') under standard biochemical conditions for the maleate*-(AH"' = -18.07 kJ . mol-', AS"' = 2.94 J . mol-' . K-') and citraconate*-(AH"' = -22.55 kJ . mol-I, AS"' = -35.92 kJ . mol-' . K-') hydration reactions were calculated. The reaction rate of malease from Ps. pseudoalculigenes was studied for both hydration reactions as a function of temperature. From these studies, the Gibbs free energies of activation for the maleate and citraconate hydration reactions catalysed by malease from Ps. pseudoalcaligenes were calculated to be 62.21 kJ . mol-' and 63.43 kJ . mol-', respectively.Biological formation of optically active synthons for the fine-chemical industry is a major area in biotechnology (Elferink et al., 1991). To this end, lyases (e.g. hydratases, ammonia-lyases) are very interesting enzymes. They do not require cofactor recycling (since addition does not involve a net reduction or oxidation), are quite stable, show an almost

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The Thermodynamics of the Krebs Cycle and Related Compounds

Cited by 75 publications

References 42 publications

Was ferrocyanide a prebiotic reagent?

Was ferrocyanide a prebiotic reagent?

Scientific Élan Vital: Entropy Deficit or Inhomogeneity as a Unified Concept of Driving Forces of Life in Hierarchical Biosphere Driven by Photosynthesis

Thermodynamics of the maleate and citraconate hydration reactions catalysed by malease from Pseudomonas pseudoalcaligenes

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