Enhanced Diffusion of Catalytically Active Enzymes

Zhang, Yifei; Hess, Henry

doi:10.1021/acscentsci.9b00228

Cited by 63 publications

(73 citation statements)

References 100 publications

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“…Enzymatic adsorption is initiated by movement of enzyme to the substrate surface in reaction solution under the influence of physical forces. The influencing physical forces are Brownian motion(Romanczuk et al 2012;Lee et al 2014;Yanagishima et al 2014;Zhao and Mason 2018;Zhang and Hess 2019), van der Waals attraction forces…”

mentioning

confidence: 99%

Interaction of enzymes with lignocellulosic materials: causes, mechanism and influencing factors

Baig

2020

Bioresour. Bioprocess.

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For the production of biofuel (bioethanol), enzymatic adsorption onto a lignocellulosic biomass surface is a prior condition for the enzymatic hydrolysis process to occur. Lignocellulosic substances are mainly composed of cellulose, hemicellulose and lignin. The polysaccharide matrix (cellulose and hemicellulose) is capable of producing bioethanol. Therefore, lignin is removed or its concentration is reduced from the adsorption substrates by pretreatments. Selected enzymes are used for the production of reducing sugars from cellulosic materials, which in turn are converted to bioethanol. Adsorption of enzymes onto the substrate surface is a complicated process. A large number of research have been performed on the adsorption process, but little has been done to understand the mechanism of adsorption process. This article reviews the mechanisms of adsorption of enzymes onto the biomass surfaces. A conceptual adsorption mechanism is presented which will fill the gaps in literature and help researchers and industry to use adsorption more efficiently. The process of enzymatic adsorption starts with the reciprocal interplay of enzymes and substrates and ends with the establishment of molecular and cellular binding. The kinetics of an enzymatic reaction is almost the same as that of a characteristic chemical catalytic reaction. The influencing factors discussed in detail are: surface characteristics of the participating materials, the environmental factors, such as the associated flow conditions, temperature, concentration, etc. Pretreatment of lignocellulosic materials and optimum range of shear force and temperature for getting better results of adsorption are recommended.

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mentioning

confidence: 99%

Interaction of enzymes with lignocellulosic materials: causes, mechanism and influencing factors

Baig

2020

Bioresour. Bioprocess.

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“…They differ only in the prefactors and a non-zero offset for D e (s). Equation (12) is never fulfilled for such D e (s) and F(s) and consequently any initial perturbation of the concentrations is smoothed out by diffusion (See Supplementary Note 2.1). However, Eq.…”

Section: Resultsmentioning

confidence: 99%

“…Although artifacts introduced by this technique have been pointed out 8,9 , recent findings using other techniques 10,11 validated the phenomenon, which is often referred to as "enhanced diffusion". The underlying mechanism is still under debate 12 . Some experiments suggest that catalysis plays a key role 3,5,13,14 , while others indicate that enhanced diffusion persists when the substrate is replaced by an inhibitor 1,4,15 .…”

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confidence: 99%

Cross-diffusion induced patterns for a single-step enzymatic reaction

2020

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Several different enzymes display an apparent diffusion coefficient that increases with the concentration of their substrate. Moreover, their motion becomes directed in substrate gradients. Currently, there are several competing models for these transport dynamics. Here, we use mathematical modeling and numerical simulations to analyze whether the enzymatic reactions can generate a significant feedback from enzyme transport onto the substrate profile. We find that this feedback can generate spontaneous spatial patterns in the enzyme distribution, with just a single-step catalytic reaction. However, patterns are formed only for a subclass of transport models. For such models, nonspecific repulsive interactions between the enzyme and the substrate, or attractive interactions between the enzyme and the product, cause the enzyme to accumulate in regions of low substrate concentration. Reactions then amplify local substrate and product fluctuations, causing enzymes to further accumulate where substrate is low. Experimental analysis of this pattern formation process could discriminate between different transport models.

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“…In this work, however, we do not require such a condition. In physiological conditions, the sizes of actual substrate-enzyme complexes either decrease (ℓ 0 > ℓ 1 ) or increase (ℓ 1 > ℓ 0 ) upon substrate binding [7]. Hereafter, the subscripts "0" and "1" denote physical values for the enzyme and the substrate-enzyme complex, respectively.…”

Section: Two-state Dimer Solutionsmentioning

confidence: 99%

“…One of the long-standing and interesting questions in the field is whether a single enzyme exhibits a motile behavior [7]. Thanks to recent developments of experimental techniques, diffusion phenomena in enzyme solutions have been studied by several groups.…”

Section: Introductionmentioning

confidence: 99%

Shear viscosity of two-state enzyme solutions

2020

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We discuss the shear viscosity of a Newtonian solution of catalytic enzymes and substrate molecules. The enzyme is modeled as a two-state dimer consisting of two spherical domains connected with an elastic spring. We take into account the enzymatic conformational dynamics, which is induced by the binding of an additional elastic spring that represents a bond between the substrate and enzyme. Employing the Boltzmann distribution weighted by the waiting times of enzymatic species in each catalytic cycle, we obtain the shear viscosity of dilute enzyme solutions as a function of substrate concentration and its physical properties. The substrate affinity distinguishes between fast and slow enzymes, and the corresponding viscosity expressions are obtained. Furthermore, we connect the obtained viscosity with the diffusion coefficient of a tracer particle in enzyme solutions.

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Enhanced Diffusion of Catalytically Active Enzymes

Cited by 63 publications

References 100 publications

Interaction of enzymes with lignocellulosic materials: causes, mechanism and influencing factors

Interaction of enzymes with lignocellulosic materials: causes, mechanism and influencing factors

Cross-diffusion induced patterns for a single-step enzymatic reaction

Shear viscosity of two-state enzyme solutions

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