scholarly journals Enzymatic Kinetics of Enzymatically Extruded Degerminated Maize Using Glucamylase

2018 ◽  
Vol 7 (2) ◽  
pp. 10 ◽  
Author(s):  
Chengye Ma ◽  
Shuangshuang Yu ◽  
Yuyan Fan ◽  
Shuhua Wu ◽  
Zhehao Zhang ◽  
...  
Keyword(s):  
Incubation Time ◽  
Reaction Rate ◽  
Reaction Rates ◽  
Enzyme Concentration ◽  
Kinetics Equation ◽  
Enzymatic Kinetics ◽  
Substrate Ph ◽  
Kinetics Of

In this study, the reaction rates of native degerminated maize, extruded degerminated maize and enzymatically extruded degerminated maize using glucoamylase were evaluated and the extrudate models were investigated. The effects of enzyme concentration, substrate pH, temperature and incubation time on the reaction rates were studied. The Lineweaver–Burk equation was used in order to obtain the parameters of the kinetics equation of catalysed hydrolysis. The results show that NDM’s vm is 0.0845g/(mL·min) and km is 0.0032, EDM’s vm is 0.6251g/(mL·min) and km is 0.0167, EEDM’s vm is 1.897g/(mL·min) and km is 0.0240. The reaction rate of EEDM is quicker than those of NDM and EDM. The kinetics equation of EEDM is in accordance with the Michaelis–Menten equation.

A KINETICS AND MECHANISTIC STUDY OF THE OXIDATION OF L-ARGININE BY QDC IN DMF-WATER MEDIUM

2021 ◽  
pp. 11-12
Author(s):  
Deepika Jain ◽  
Shilpa Rathor
Keyword(s):  
Perchloric Acid ◽  
Reaction Rate ◽  
Main Product ◽  
Activation Parameters ◽  
Reaction Rates ◽  
Mechanistic Study ◽  
Water Medium ◽  
Volume Percentage ◽  
Kinetics Of Oxidation ◽  
Kinetics Of

The present paper describes the kinetics of oxidation of l-Arginine by QDC in the presence of perchloric acid in 30% DMF-H O(v/v) medium at 2 + 40⁰C spectrophotometrically at λ =354nm. The reaction is rst order with respect to [QDC], [H ], and [substrate]. The reaction rate increased with max increasing volume percentage of DMF in reaction mixture. Michaelis- Menten type kinetic was observed with l-Arginine. The reaction rates were studied at different temperature and the activation parameters has been computed. The main product was identied as Cr (III) and 4-Guanidino buteraldehyde.

scholarly journals The kinetics of the reduction of the lipophilic quinone avarone by N-alkyl-1,4-dihydronicotinamides of various lipophilicities

1999 ◽  
Vol 64 (11) ◽  
pp. 647-654 ◽  
Author(s):  
Mario Zlatovic ◽  
Dusan Sladic ◽  
Miroslav Gasic
Keyword(s):  
Cationic Surfactants ◽  
Reaction Rate ◽  
Anionic Surfactants ◽  
Reaction Rates ◽  
Biologically Active ◽  
Ionic Surfactants ◽  
Protic Solvent ◽  
Model Compounds ◽  
Kinetics Of ◽  
Long Chain

Several NADH model compounds, N-alkyl-1,4-dihydronicotinamides, some of them possessing amphiphilic properties, have been synthesized, and the kinetics of their reaction with a biologically active liphophilic quinone, avarone, has been studied in a protic solvent both in the presence and absence of cationic, anionic or non-ionic surfactants. In the absence of micellar agents, the medium- and long-chain N-dodecyl (3) and N-heptadecyl (4) derivatives show a significant increase in the reaction rates compared to other model compounds, due to the stabilization of the semiquinone intermediate. Anionic surfactants retard the reaction, non-ionic surfactants slightly accelerate the reaction with the short-chain derivatives, and retard the reaction with the medium- and long-chain derivatives, and the cationic surfactants increase the reaction rate with all derivatives except the long-chain 4. The results support the e-p-e mechanism of the reduction of lipophilic quinones byNADHmodels in protic medium.

scholarly journals PHYSICOCHEMICAL PROPERTIES OF THE PROTEOLYTIC ENZYME FROM THE LATEX OF THE MILKWEED, ASCLEPIAS SPECIOSA TORR. SOME COMPARISONS WITH OTHER PROTEASES

1940 ◽  
Vol 23 (3) ◽  
pp. 289-300 ◽  
Author(s):  
Theodore Winnick ◽  
Alva R. Davis ◽  
David M. Greenberg
Keyword(s):  
Reaction Rate ◽  
Enzyme Concentration ◽  
Second Order ◽  
Urea Solution ◽  
Reaction Products ◽  
Clotting Time ◽  
Milk Clotting ◽  
Enzyme Substrate ◽  
Asclepias Speciosa ◽  
Kinetics Of

1. The kinetics of milk clotting by asclepain, the protease of Asclepias speciosa, were investigated. At higher concentrations of enzyme, the clotting time was inversely proportional to the enzyme concentration. 2. The digestion of casein and hemoglobin in 6.6 M urea by asclepain follows the second order reaction rate. The rate was roughly second order for casein in water. 3. Evaluation of the nature of the enzyme-substrate intermediate indicates that one molecule of asclepain combines with one molecule of casein or hemoglobin in urea solution. 4. Inhibition by the reaction products was deduced from the fact that the digestion velocity of hemoglobin in urea solution varied with the asclepain concentration in agreement with the Schütz-Borissov rule.

Kinetics of PbTiO3 perovskite phase formation via an interfacial reaction

2002 ◽  
Vol 17 (2) ◽  
pp. 407-412 ◽  
Author(s):  
Yun-Mo Sung ◽  
Woo-Chul Kwak ◽  
Sungtae Kim
Keyword(s):  
Reaction Rate ◽  
Arrhenius Plot ◽  
Perovskite Phase ◽  
Diffusion Constant ◽  
Reaction Rate Constant ◽  
Kinetics Equation ◽  
Average Diffusion Coefficient ◽  
Average Diffusion ◽  
Activation Energy For Diffusion ◽  
Kinetics Of

The kinetics of the formation of PbTiO3 at the PbO/TiO2 interface has been analyzed. The flux of Pb2+ and O2− ions through the PbTiO3 layer was used to derive the kinetics equation for the formation of the PbTiO3 phase. On the basis of the parabolic growth kinetics of the PbTiO3 interlayer, the reaction rate constant (k) for PbTiO3 formation was determined as a function of the average diffusion coefficient of the Pb2+ ions (DPb2+). By employment of the data from diffusion couple experiments and the free energy values for the formation of the PbTiO3 phase () into the present kinetics equation, DPb2+ in the PbTiO3 interlayer was calculated with respect to the corresponding temperature. The activation energy for diffusion (Q) and the diffusion constant (D0) of Pb2+ ions in the PbTiO3 layer could be evaluated from the Arrhenius plot of DPb2+.

scholarly journals Kinetic Explanations for the Sequence Biases Observed in the Nonenzymatic Copying of RNA Templates

2021 ◽  
Author(s):  
Dian Ding ◽  
Lijun Zhou ◽  
Constantin Giurgiu ◽  
Jack W. Szostak
Keyword(s):  
Nucleic Acid ◽  
Origin Of Life ◽  
Reaction Rate ◽  
Nearest Neighbor ◽  
Reaction Rates ◽  
Primer Extension ◽  
Extension Rate ◽  
The Origin Of Life ◽  
Noncanonical Nucleotides ◽  
Kinetics Of

ABSTRACTThe identification of nonenzymatic pathways for nucleic acid replication is a key challenge in understanding the origin of life. We have previously shown that nonenzymatic RNA primer extension using 2-aminoimidazole (2AI) activated nucleotides occurs primarily through an imidazolium-bridged dinucleotide intermediate. The reactive nature and preorganized structure of the intermediate increase the efficiency of primer extension but remain insufficient to drive extensive copying of RNA templates containing all four canonical nucleotides. To understand the factors that limit RNA copying, we synthesized all ten 2AI-bridged dinucleotide intermediates and measured the kinetics of primer extension in a model. The affinities of the ten dinucleotides for the primer/template/helper complexes vary by over 7,000-fold, consistent with nearest neighbor energetic predictions. Surprisingly, the reaction rates at saturating intermediate concentrations still vary by over 15-fold, with the most weakly binding dinucleotides exhibiting a lower maximal reaction rate. Certain noncanonical nucleotides can decrease sequence dependent differences in affinity and primer extension rate, while monomers bridged to short oligonucleotides exhibit enhanced binding and reaction rates. We suggest that more uniform binding and reactivity of imidazolium-bridged intermediates may lead to the ability to copy arbitrary template sequences under prebiotically plausible conditions.

Eclogitization kinetics of continental granulites : quantification and implications

2020 ◽  
Author(s):  
Marie Baisset ◽  
Loic Labrousse ◽  
Alexandre Schubnel
Keyword(s):  
Rheological Behavior ◽  
Reaction Rate ◽  
Experimental Studies ◽  
Reaction Rates ◽  
First Order ◽  
Piston Cylinder ◽  
Ductile Flow ◽  
Convergence Zones ◽  
Kinetics Of ◽  
Type Apparatus

<p><span>When implicated in convergence zones, granulites of the lower continental crust are expected to eclogitize at depth.When exposed in the field such units show a bimodal rheological behavior between fracturing of the protolith rock (granulites) and ductile flow of the transformed parts (eclogites). It seems therefore that a competition exists between the rate at which the rocks are loaded in stress and the rate at which they transform, i.e. the overall eclogitization kinetics. The aim of the work presented here is to quantify the kinetics of the metamorphic reactions involved in eclogitization by estimating the reaction rates in plagioclase-bearing assemblages<span>  </span>submitted to different P-T conditions over different time spans. For this, experiments have been performed in piston-cylinder apparatus on aggregates derived from natural granulites. Special attention is paid to the location where nucleation starts and how it propagates in and between the grains. In this prospect, the presence of garnet and cpx in the plagioclase matrix is a first order control on the reaction process. This work follows previous experimental studies (e.g. Shi et al., 2017, Incel et al., 2018) which show that reaction-enhanced embrittlement may be key for fracturing at high pressure. It has been proposed that transient properties of the rocks induced by the very beginning of the reaction (e.g. volume change, small grain size nucleation products) can lead to brittle instabilities. As we assume that the rheological behavior of the crust is controlled by a competition between reaction rate and strain rate, experiments involving deformation of granulites while undergoing eclogitization are required. Preliminary results performed on Griggs-type apparatus, which constitutes the best tool for that, will also be presented.</span></p>

scholarly journals Estimation of Reaction Rates of Transesterification Pathways

2021 ◽  
Vol 3 ◽  
Author(s):  
Mario Alberto Pérez-Méndez ◽  
Gladys Jiménez-García ◽  
Rafael Huirache-Acuña ◽  
Rafael Maya-Yescas
Keyword(s):  
Sodium Hydroxide ◽  
Fatty Acid Methyl Esters ◽  
Reaction Rate ◽  
Methyl Esters ◽  
Reaction Rates ◽  
Reaction Engineering ◽  
Reaction Pathways ◽  
Chemical Reactors ◽  
Acid Methyl ◽  
Kinetics Of

Experimental estimation of reaction rates is a common aspect of reaction engineering because reaction kinetics are the base of the design of chemical reactors. However, it is not easy to follow complex reactions as it is the case of transesterification of triglycerides in presence of sodium hydroxide. Identifying the possible reaction pathways taking place as ionic and sequential, starting with the inorganic formation of methoxide, and followed by each one of the three organic transesterification steps of virgin soybean oil, deeper understanding about kinetics of this reacting path has been obtained. Reaction rate evaluations were performed by following the solution’s pH, based on a 24–1 design of experiments, making possible to estimate the rate constants. Additionally, it was observed that there is an optimum amount of sodium hydroxide feed to the process, therefore it is possible to minimize its addition, which favors diminishing the volume of leaching water. The best yield to fatty acid methyl esters, using the minimum amount of sodium hydroxide, was 98.84 wt%, which is highly competitive.

STUDYING THE KINETIC CHARACTERISTICS OF THE EXTRACTION OF ANTHOCYANINS FROM THE SQUEEZE OF KRASNOSTOP ZOLOTOVSKY

2020 ◽  
Author(s):  
M.A. Egyan ◽  
Keyword(s):  
Reaction Rate ◽  
Sugar Content ◽  
Extraction Process ◽  
Efficiency Coefficient ◽  
Kinetic Characteristics ◽  
Reaction Rate Constants ◽  
Solids Content ◽  
Kinetics Of ◽  
Process Speed

The article shows studies characterizing the quality of the squeeze: the mechanical composition of the squeeze is determined, the structural moisture of each component is determined, the sugar content in the formed process of sedimentation of the juice and its acidity are determined refractometrically. The kinetics of anthocyanins extraction was determined in two ways, the solids content in the extract was calculated, and the reaction rate constants of the extraction process and the efficiency coefficient of ultrasonic amplification of the extraction process speed were calculated.

Thermal Decomposition Kinetics of Glyphosate (GP) and its Metabolite Aminomethylphosphonic Acid (AMPA)

2019 ◽  
Author(s):  
Milad Narimani ◽  
Gabriel da Silva
Keyword(s):  
Thermal Decomposition ◽  
Reaction Rate ◽  
Decomposition Kinetics ◽  
Rate Theory ◽  
Thermal Decomposition Mechanism ◽  
Treatment Processes ◽  
Aminomethylphosphonic Acid ◽  
Reaction Rate Theory ◽  
Decomposition Chemistry ◽  
Kinetics Of

Glyphosate (GP) is a widely used herbicide worldwide, yet accumulation of GP and its main byproduct, aminomethylphosphonic acid (AMPA), in soil and water has raised concerns about its potential effects to human health. Thermal treatment processes are one option for decontaminating material containing GP and AMPA, yet the thermal decomposition chemistry of these compounds remains poorly understood. Here, we have revealed the thermal decomposition mechanism of GP and AMPA by applying computational chemistry and reaction rate theory methods. <br>

Particle Destabilization in Turbulent Pipe Flow

1989 ◽  
Vol 21 (6-7) ◽  
pp. 435-442 ◽  
Author(s):  
B. Döll
Keyword(s):  
Pipe Flow ◽  
Reaction Rate ◽  
Turbulent Pipe Flow ◽  
Cationic Polymers ◽  
Flow Conditions ◽  
Polyelectrolyte Adsorption ◽  
Charge Neutralization ◽  
Silica Suspensions ◽  
Kinetics Of ◽  
Turbulent Flow Conditions

Silica suspensions (pH = 6.8) and three different cationic polymers were used to study the kinetics of charge neutralization by polyelectrolyte adsorption. The experiments were performed in a continuous flow pipe reactor under steady state turbulent flow conditions. The charge neutralization was monitored by electrophoretic mobility (EPM) measurements of the suspended particles as a function of time after polyelectrolyte audition. The results show the dependency of the destabilization reaction rate on flow and polymer characteristics.

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