Kinetics of the Immobilized Enzymatic Reaction

2020 ◽  
pp. 23-32
Author(s):  
Debabrata Das ◽  
Debayan Das
Keyword(s):  
Enzymatic Reaction ◽  
Kinetics Of

scholarly journals Controlling the Kinetics of an Enzymatic Reaction through Enzyme or Substrate Confinement into Lipid Mesophases with Tunable Structural Parameters

2020 ◽  
Vol 21 (14) ◽  
pp. 5116
Author(s):  
Marco Mendozza ◽  
Arianna Balestri ◽  
Costanza Montis ◽  
Debora Berti
Keyword(s):  
Reaction Kinetics ◽  
Self Assembly ◽  
Liquid Crystalline ◽  
Structural Parameters ◽  
Enzymatic Reaction ◽  
X Ray Scattering ◽  
Nitrophenyl Phosphate ◽  
Vis Spectroscopy ◽  
Kinetics Of ◽  
Enzyme Alkaline Phosphatase

Lipid liquid crystalline mesophases, resulting from the self-assembly of polymorphic lipids in water, have been widely explored as biocompatible drug delivery systems. In this respect, non-lamellar structures are particularly attractive: they are characterized by complex 3D architectures, with the coexistence of hydrophobic and hydrophilic regions that can conveniently host drugs of different polarities. The fine tunability of the structural parameters is nontrivial, but of paramount relevance, in order to control the diffusive properties of encapsulated active principles and, ultimately, their pharmacokinetics and release. In this work, we investigate the reaction kinetics of p-nitrophenyl phosphate conversion into p-nitrophenol, catalysed by the enzyme Alkaline Phosphatase, upon alternative confinement of the substrate and of the enzyme into liquid crystalline mesophases of phytantriol/H2O containing variable amounts of an additive, sucrose stearate, able to swell the mesophase. A structural investigation through Small-Angle X-ray Scattering, revealed the possibility to finely control the structure/size of the mesophases with the amount of the included additive. A UV–vis spectroscopy study highlighted that the enzymatic reaction kinetics could be controlled by tuning the structural parameters of the mesophase, opening new perspectives for the exploitation of non-lamellar mesophases for confinement and controlled release of therapeutics.

Effect of Hypertonic Sucrose Upon the Immune Bactericidal Reaction

1970 ◽  
Vol 1 (1) ◽  
pp. 51-55
Author(s):  
Louis H. Muschel ◽  
Linda J. Larsen
Keyword(s):  
Cell Death ◽  
Cell Wall ◽  
Enzymatic Reaction ◽  
Inhibitory Effect ◽  
Lag Phase ◽  
Inner Membrane ◽  
Bactericidal Antibody ◽  
Kinetics Of ◽  
Free Serum ◽  
Supporting Structures

This study was performed to determine the mechanism whereby hypertonic sucrose inhibits the immune bactericidal reaction. Other investigators had postulated that the initial attack of complement (C) on the cell wall was followed with lysozyme-containing whole serum by an enzymatic reaction upon the peptidoglycan substrate resulting in cell death. In the absence of serum lysozyme, secondary lethal changes might occur from damage to the cell's inner membrane as a result of osmotic forces in the presence of a defective cell wall. Hypertonic sucrose giving rise to plasmolysis and protection of the inner membrane was presumed to differentially inhibit the immune response mediated by lysozyme-free serum. The experimental results observed in this investigation have indicated, however, that the inhibitory effect of sucrose upon the bactericidal reaction may be explained simply by its anticomplementary effect and not by any effect on the bacterial cell. This view was supported by the following observations: (i) the comparability of the inhibitory effect of sucrose upon the immune hemolytic and bactericidal reactions, (ii) the comparable percentage loss in bactericidal activity of whole serum and lysozyme-free serum resulting from hypertonic sucrose, (iii) bactericidal antibody titrations were relatively unaffected and C titrations markedly inhibited by sucrose, (iv) the inhibitory effect of sucrose on the bactericidal reaction was unaffected by prior growth of the organism in the presence of sucrose, (v) the kinetics of the bactericidal reactivity of lysozyme-free serum in hypertonic sucrose, compared with whole serum, did not reveal a prolonged lag phase with lysozyme-free serum, but simply diminished reactivity at all times. These observations are compatible with the view that the C attack upon the outer surface of gram-negative bacteria, which plays a part in the cell's permeability control, may account for cell death. In this regard, the immune bactericidal reaction is quite comparable to the lysis of red cells or nucleated cells by C despite the lack of overt lysis in bacteria, probably because of their underlying supporting structures.

Enzymatic Reaction Kinetics of Papain-Extracted Collagen from Bighead Carp Scales

2015 ◽  
Vol 727-728 ◽  
pp. 56-60
Author(s):  
Min Li ◽  
Liu Meng Chen ◽  
Bo Quan Jiang
Keyword(s):  
Reaction Kinetics ◽  
Reaction Rate ◽  
Enzymatic Reaction ◽  
Raw Material ◽  
Bighead Carp ◽  
Fish Waste ◽  
Biomedical Material ◽  
Production Output ◽  
And Control ◽  
Kinetics Of

Collagen, as an important biomedical material, has been widely used in medical industry. Fish waste (scales, skins, bones, fins and swim bladders) is a kind of newly developed alternative collagen raw material.This paper uesd papain as enzyme and local bighead fish scales as raw material to extract collagen. More attention was paid to the study on enzymatic reaction kinetics of papain-extracted collagen. The results showed that two kinds of kinetic models(Michaelis-Menten equations and exponential type dynamic equations) at 20, 25 and 28°C were established, respectively and experimentally proved to be basically in agreement with the actual values. These models have a great significance to predict, adjust and control the reaction rate and production output under different conditions.

Use of whey permeate containing in situ synthesised galacto-oligosaccharides for the growth and preservation of Lactobacillus plantarum

2013 ◽  
Vol 80 (3) ◽  
pp. 374-381 ◽  
Author(s):  
Marina Golowczyc ◽  
Carlos Vera ◽  
Mauricio Santos ◽  
Cecilia Guerrero ◽  
Paula Carasi ◽  
...  
Keyword(s):  
Lactobacillus Plantarum ◽  
Culture Media ◽  
Enzymatic Reaction ◽  
Raw Material ◽  
Whey Permeate ◽  
Cheese Industry ◽  
Potential Impact ◽  
And Storage ◽  
Kinetics Of

Galacto-oligosaccharides (GOS) are prebiotics that have a beneficial effect on human health by promoting the growth of probiotic bacteria in the gut. GOS are commonly produced from lactose in an enzymatic reaction catalysed by β-galactosidase, named transglycosylation. Lactose is the main constituent of whey permeate (WP), normally wasted output from the cheese industry. Therefore, the main goal of this work was to optimise the synthesis of GOS in WP using β-galatosidase from Aspergillus oryzaea. WP and whey permeate enzymatically treated (WP-GOS) were used as culture media of Lactobacillus plantarum 299v. Lb. plantarum 299v attained the stationary phase in approximately 16 h, reaching 3·6 and 4·1×108 CFU/ml in WP and WP-GOS, respectively. The in situ synthesised GOS were not consumed during growth. No significant differences were observed in the growth kinetics of microorganisms in both media. After fermentation, microorganisms were dehydrated by freeze-drying and spray-drying and stored. The recovery of microorganisms after fermentation, dehydration and storage at 4 °C for at least 120 d was above 108 CFU/g. These studies demonstrated that WP is an appropriate substrate for the synthesis of GOS and the obtained product is also adequate as culture medium of Lb. plantarum 299v. The coexistence of GOS and dehydrated viable probiotic microorganisms, prepared using an effluent as raw material, represents the main achievement of this work, with potential impact in the development of functional foods.

scholarly journals On a Method of Determining the Mechanism of an Enzymatic Reaction the Kinetics of Which is Known.

1949 ◽  
Vol 3 ◽  
pp. 493-504 ◽  
Author(s):  
J. A. Christiansen ◽  
V. Eriksson ◽  
Terttu Laaksonen ◽  
Maire Hakala
Keyword(s):  
Enzymatic Reaction ◽  
Kinetics Of

Programmable Dynamic Steady States in ATP-Driven Non-Equilibrium DNA Systems

2019 ◽  
Author(s):  
Laura Heinen ◽  
Andreas Walther
Keyword(s):  
Self Assembly ◽  
Soft Matter ◽  
Enzymatic Reaction ◽  
Reaction Network ◽  
Steady States ◽  
Supramolecular Systems ◽  
Kinetics Of ◽  
Average Bond ◽  
Full Synchronization ◽  
Non Equilibrium

<div><div><div><p>Inspired by the dynamics of the dissipative self-assembly of microtubules, chemically fueled synthetic systems with transient lifetimes are emerging for non-equilibrium materials design. However, realizing programmable or even adaptive structural dynamics has proven challenging because it requires synchronization of energy uptake and dissipation events within true steady states, which remains difficult to orthogonally control in supramolecular systems. Here, we demonstrate full synchronization of both events by ATP-fueled activation and dynamization of covalent DNA bonds via an enzymatic reaction network of concurrent ligation and cleavage. Critically, the average bond ratio and the frequency of bond exchange are imprinted into the energy dissipation kinetics of the network and tunable through its constituents. We introduce temporally and structurally programmable dynamics by polymerization of transient, dynamic covalent DNA polymers with adaptive steady-state properties in dependence of ATP fuel and enzyme concentrations. This approach enables generic access to non-equilibrium soft matter systems with adaptive and programmable dynamics.</p></div></div></div>

Apparent Parameters of Enzymatic Plate-Gap Electrode

2005 ◽  
Vol 10 (3) ◽  
pp. 211-211 ◽  
Author(s):  
I. Kaunietis ◽  
R. Šimkus ◽  
V. Laurinavičius ◽  
F. Ivanauskas
Keyword(s):  
Enzymatic Reaction ◽  
Reaction Diffusion ◽  
Wide Range ◽  
Steady State Current ◽  
Substrate Diffusion ◽  
Michaelis Constants ◽  
Complete Set ◽  
Kinetics Of ◽  
Substrate Concentrations ◽  
Biosensor Response

It was suggested that reaction-diffusion conditions in pores of bulk enzymatic electrode resemble particular conditions in thin enzyme filled gap between parallel conducting plates. The plate-gap model of porous enzymatic electrode is based on the diffusion equations containing a nonlinear term related to the Michaelis-Menten kinetics of the enzymatic reaction inside the gap. Steady state current was calculated for the wide range of given values of substrate diffusion coefficient, depth of the gap and substrate concentrations. Simple approximate relationships between “apparent” parameters of amperometric biosensor (maximal currents and apparent Michaelis constants) and given values of diffusion characterising parameters were derived. Association of these dependences with previously reported relationships led to derive approximate formulae that bind apparent parameters with the complete set of given parameters of the plate-gap enzymatic electrode. The limit case of slow diffusion into deep gap was also characterised. In this specific case, the highest numerical values of the apparent parameters were obtained. However, this gain is achievable at the expense of biosensor response time.

Effect of temperature on the equilibrium and kinetics of galactose, glucose, and lactose adsorption on a cation exchanger

2014 ◽  
Vol 68 (12) ◽  
Author(s):  
Łukasz Wiśniewski ◽  
Katarína Vaňková ◽  
Pavel Ačai ◽  
Milan Polakovič
Keyword(s):  
Mass Transfer ◽  
Cation Exchanger ◽  
Enzymatic Reaction ◽  
Breakthrough Curves ◽  
Axial Dispersion ◽  
Effect Of Temperature ◽  
Transfer Resistance ◽  
Adsorption Equilibria ◽  
Intraparticle Mass Transfer ◽  
Kinetics Of

AbstractGalacto-oligosaccharides are typically produced by an enzymatic reaction when the post-reaction mixture contains considerable amounts of lactose and glucose and a smaller amount of galactose. In order to develop a process of chromatographic removal of saccharide impurities, adsorption equilibria and kinetics of these di- and monosaccharides were investigated for Diaion UBK 530, an industrialgrade strong cation-exchanger in the Na+ form. Frontal chromatographic experiments were carried out in the temperature range of 30–70°C and a broad interval of saccharide concentrations up to 350 g L−1. Breakthrough curves were described using the equilibrium-dispersive model with the linear adsorption isotherm. Both the distribution and the axial dispersion coefficient values depended on the saccharide molecule type and size. No significant effect of temperature or concentration on the distribution coefficient was observed. The apparent dispersion coefficients of all saccharides exhibited some decrease with the temperature, which was caused by the decrease of the intraparticle mass transfer resistance. An analysis showed that both the intraparticle mass transfer and the axial dispersion had a significant influence on the front dispersion.

scholarly journals Computational Modelling of Biosensors with an Outer Perforated Membrane

2009 ◽  
Vol 14 (1) ◽  
pp. 85-102 ◽  
Author(s):  
K. Petrauskas ◽  
R. Baronas
Keyword(s):  
Diffusion Coefficient ◽  
Effective Diffusion Coefficient ◽  
Effective Diffusion ◽  
Enzymatic Reaction ◽  
Computational Modelling ◽  
Reaction Diffusion ◽  
Reaction Diffusion Equations ◽  
D Model ◽  
Kinetics Of ◽  
Biosensor Response

This paper presents one-dimensional (1-D) and two-dimensional (2-D) in-space mathematical models for amperometric biosensors with an outer perforated membrane. The biosensor action was modelled by reaction-diffusion equations with a nonlinear term representing the Michaelis-Menten kinetics of an enzymatic reaction. The conditions at which the 1-D model can be applied to simulate the biosensor response accurately were investigated numerically. The accuracy of the biosensor response simulated by using 1-D model was evaluated by the response simulated with the corresponding 2-D model. A procedure for a numerical evaluation of the effective diffusion coefficient to be used in 1-D model was proposed. The numerically calculated effective diffusion coefficient was compared with the corresponding coefficients derived analytically. The numerical simulation was carried out using the finite difference technique.

scholarly journals Phase-Plane Geometries in Coupled Enzyme Assays

2018 ◽  
Author(s):  
Justin Eilertsen ◽  
Wylie Stroberg ◽  
Santiago Schnell
Keyword(s):  
Time Course ◽  
Vector Fields ◽  
Phase Plane ◽  
Dynamical Behavior ◽  
Enzymatic Reaction ◽  
Geometric Interpretation ◽  
Slow Manifolds ◽  
Singular Perturbation Analysis ◽  
Kinetics Of

The determination of a substrate or enzyme activity by coupling of one enzymatic reaction with another easily detectable (indicator) reaction is a common practice in the biochemical sciences. Usually, the kinetics of enzyme reactions is simplified with singular perturbation analysis to derive rate or time course expressions valid under the quasi-steady-state and reactant stationary state assumptions. In this paper, the dynamical behavior of coupled enzyme catalyzed reaction mechanisms is studied by analysis of the phase-plane. We analyze two types of time-dependent slow manifolds - Sisyphus and Laelaps manifolds - that occur in the asymptotically autonomous vector fields that arise from enzyme coupled reactions. Projection onto slow manifolds yields various reduced models, and we present a geometric interpretation of the slow/fast dynamics that occur in the phase-planes of these reactions. <br>

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