The effect of reversible binding of the autocatalyst on the lateral instability of reaction fronts

Jakab, Éva; Horváth, Dezsö; Tóth, Ágota; Merkin, J. H.; Scott, Stephen K.

doi:10.1016/s0009-2614(01)00615-7

Cited by 18 publications

(9 citation statements)

References 11 publications

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“…The first observation implies that the autocatalytic step is a second-order reaction with respect to the kinetics (19), whereas the second observation requires that the substrate reacts directly with the autocatalyst form of the enzyme (20,21). These observations impose slight modifications on the previous model (12).…”

Section: Model Calculationsmentioning

confidence: 99%

Concentration-Dependent Front Velocity of the Autocatalytic Hydrogenase Reaction

Bodó

Branca

Tóth

et al. 2009

Biophysical Journal

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HynSL hydrogenase from Thiocapsa roseopersicina was applied to catalyze the oxidation of molecular hydrogen in a new, improved, thin-layer reaction chamber. Investigation of the nature of this catalysis via the development of reduced benzyl viologen showed clearly the typical characteristics of an autocatalytic reaction: propagation of a reaction front originating from a single point, with a constant velocity of front propagation. The dependence of the reaction velocity on enzyme concentration was a power function with a positive enzyme concentration threshold, with an exponent of 0.4 +/- 0.05. This indicates that the autocatalyst is an enzyme form. The front velocity decreased on increase of the electron acceptor concentration, as a sign that the autocatalyst interacts directly with the final electron acceptor. Overall, it may be concluded that the autocatalyst is an enzyme form in which [FeS]distal is reduced. Model calculations corroborate this. Because the reduction of all [FeS] clusters would be possible in a nonautocatalytic reaction, we hypothesize a small conformational change in the enzyme, catalyzed by the autocatalyst, which removes a block in the electron flow in either [NiFe] --> [FeS]proximal or the [FeS]proximal --> [FeS]distal reaction step, or removes a block of the penetration of gaseous hydrogen from the surface to the [NiFe] cluster.

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Section: Model Calculationsmentioning

confidence: 99%

Concentration-Dependent Front Velocity of the Autocatalytic Hydrogenase Reaction

Bodó

Branca

Tóth

et al. 2009

Biophysical Journal

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“…In the chlorite-iodide-malonic acid reaction the presence of starch suppresses the homogeneous oscillations by shifting the Hopf-bifurcation allowing the formation of Turing patterns. The same approach in simple autocatalytic reaction fronts has led to the lowering of the free autocatalyst concentration behind the front, 31,38 through which the flux of the autocatalyst decreases at the reaction zone allowing the destabilizing flux of the reactant to dominate and therefore leads to the appearance of cellular fronts.…”

Section: Introductionmentioning

confidence: 99%

Diffusion-driven instabilities by immobilizing the autocatalyst in ionic systems

Tóth

Horváth

2015

Chaos: An Interdisciplinary Journal of Nonlinear Science

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Spatiotemporal coupling of an autocatalytic chemical reaction between ions with diffusion yields various types of reaction-diffusion patterns. The driving force is short range activation and long range inhibition which can be achieved by selective binding of the autocatalyst even for ions with equal mobility. For Turing and lateral instability, we show that identical charge on the autocatalyst and its counterpart has a stabilizing effect on the base state, while opposite charge on them favors the formation of spatial patterns with reversible binding.

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“…loss of symmetry [24,25]. There are two conditions which have to be valid in order for a simple autocatalytic front to exhibit diffusive instability: the autocatalysis has to be strong (i.e., the front has to be a ''pushed type'' [26]) and the flux of the reactant towards the front has to be greater than that of the product [24,25]. The first cellular structure with a small amplitude was presented experimentally in the iodate-arseneous acid reaction when the autocatalyst iodide was bound by cyclodextrine [27].…”

Section: Introductionmentioning

confidence: 99%

Double-diffusive cellular fingering in the horizontally propagating fronts of the chlorite–tetrathionate reaction

Rica

Pópity-Tóth

Horváth

et al. 2010

Physica D: Nonlinear Phenomena

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a b s t r a c tHorizontally propagating chemical fronts have been studied in the acid-catalyzed chlorite-tetrathionate reaction. Unusual cellular fingers develop in a relatively thin solution layer. Double-diffusive convection is among the driving forces in the pattern formation arising from the addition of a polyelectrolyte which immobilizes and reversibly removes the autocatalyst hydrogen ion in a controlled manner and drastically slows down the front. Convection therefore becomes significant in the thin horizontal solution layer. To corroborate our results we have measured the solution densities and viscosities, and determined the diffusion coefficients by PFGSE 1 H-NMR.

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The effect of reversible binding of the autocatalyst on the lateral instability of reaction fronts

Cited by 18 publications

References 11 publications

Concentration-Dependent Front Velocity of the Autocatalytic Hydrogenase Reaction

Concentration-Dependent Front Velocity of the Autocatalytic Hydrogenase Reaction

Diffusion-driven instabilities by immobilizing the autocatalyst in ionic systems

Double-diffusive cellular fingering in the horizontally propagating fronts of the chlorite–tetrathionate reaction

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