Isotopic Effect on the Kinetic of Thermal Denaturation of Ceruloplasmin

1985 ◽  
Vol 40 (7-8) ◽  
pp. 551-554 ◽  
Author(s):  
L. Sportelli ◽  
A. Desideri ◽  
A. Campaniello
Keyword(s):  
Thermal Denaturation ◽  
Charge Transfer Band ◽  
Type I ◽  
Protein Solution ◽  
First Order ◽  
Irreversible Denaturation ◽  
Optical Density Change ◽  
Kinetics Of ◽  
Protein Active Site ◽  
Denaturation Process

Abstract The kinetics of thermal denaturation of ceruloplasmin in water and in water with different percentage of D20 in the temperature range 25 - 85 °C, following the optical density change of the 610 nm charge transfer band of the protein has been investigated. A temperature Tt ≃ 65 °C above which an irreversible denaturation process of the protein active site takes place has been found. The kinetics of the denaturation process of the protein are fitted by two first order reactions, which have been assigned to a different thermal denaturation behaviour of the two Cu2+ type I sites existing in the protein. Addition of D2O to the protein solution affects the two kinetics in a different way, i.e. the rate of one of them is increased whilst that of the other is decreased. The different effect of D2O on the kinetics of disruption of the two copper sites is discussed in terms of different location and degree of hydrophobicity of the two Cu2+ type I sites.

scholarly journals Molecular mechanisms of the irreversible thermal denaturation of guinea-pig liver transglutaminase

1990 ◽  
Vol 266 (2) ◽  
pp. 487-490 ◽  
Author(s):  
S Nury ◽  
J C Meunier
Keyword(s):  
Thermal Denaturation ◽  
Molecular Mechanisms ◽  
Molecular Events ◽  
Sds Page ◽  
Irreversible Denaturation ◽  
Enzyme Molecules ◽  
Kinetics Of ◽  
Guinea Pig Liver ◽  
Step Mechanism ◽  
Rule Out

When transglutaminase is heated at temperatures above 40 degrees C, it loses its activity according to a two-step mechanism [Nury, Meunier & Mouranche (1989) Eur. J. Biochem. 180, 161-166]: N→X(TD)→D However, the nature of the molecular events responsible for the irreversible denaturation is still unknown. Investigation of the effects of dithiothreitol and 5,5′-dithiobis-2-nitrobenzoate on the kinetics of inactivation, titrations of ammonia released by deamidation and of thiol groups on the native and denatured enzymes and SDS/PAGE rule out the involvement of covalent processes during the denaturation of transglutaminase at 55 degrees C and pH 7. Of the two possible kinds of non-covalent events, i.e. unfolding of the polypeptide chain and aggregation of enzyme molecules, we show that both occur, though only the former process is responsible for the denaturation. The latter process, aggregation, follows the unfolding of the molecules.

scholarly journals Remediation of Crystal Violet Dye Aqueous Solution Using Agro Waste Based Activated Carbon: Equilibrium and Kinetics Studies

2020 ◽  
pp. 1-11
Author(s):  
Chukwunonso Chukwuzuloke Okoye ◽  
Okechukwu Dominic Onukwuli ◽  
Chinenye Faith Okey- Onyesolu ◽  
Ifeoma Amaoge Obiora- Okafo
Keyword(s):  
Aqueous Solution ◽  
Kinetic Data ◽  
Adsorption Process ◽  
Particle Diffusion ◽  
Type I ◽  
First Order ◽  
Equilibrium And Kinetics ◽  
Equilibrium Data ◽  
Intra Particle Diffusion ◽  
Kinetics Of

Remediation of crystal violet (CV) dye aqueous solution was attempted using acid activated raphia hookeri seeds (AARHS) as adsorbent. Adsorption equilibrium and kinetics of CV dye uptake onto AARHS were examined in series of experimental runs, and effects of contact time and initial CV dye concentrations were investigated at different solution temperatures (303 K, 313 K and 323 K). Equilibrium and kinetic data modeling of the adsorption process was performed using selected theoretical methods. Four different forms of Langmuir (type I, II, III and IV) and Freundlich isotherms were considered for fitting the equilibrium data while zero order, first order, pseudo-first order (PFO), second order, types I, II, III and IV pseudo-second order (PSO) and intra-particle diffusion models were selected to describe the kinetics of the adsorption process. Error functions including coefficient of determination (R2), root mean square error (RMSE), chi square (χ2) and average relative error (ARE) were employed to reveal model of best fit. Results obtained from error value computations show that the equilibrium data best followed Freundlich isotherm, which indicates multilayer adsorption of CV dye onto AARHS. The calculated Freundlich’s adsorption intensity values at different temperatures reveal the favourability of the adsorption process. PSO type I, II and IV best fitted the kinetic data compared to other investigated models. Intra-particle diffusion plots depict that the adsorption process of CV dye onto AARHS is a two-step process and also, intra-particle diffusion is not the only rate-limiting step.

Comparison of Temperature Metrics of Heating-Induced Damage

2002 ◽  
Author(s):  
Neil T. Wright
Keyword(s):  
Thermal Denaturation ◽  
Transition State Theory ◽  
Type I Collagen ◽  
Arrhenius Equation ◽  
Frequency Factor ◽  
State Theory ◽  
Type I ◽  
Denaturation Temperature ◽  
First Order ◽  
First Order Phase

The temperature dependence of the rate of denaturation of Type I collagen due to heating is described well by chemical kinetics via the Arrhenius equation or transition state theory (TST) [1, 2, 3], each of which requires two material parameters. Nevertheless, many have sought to find a single convenient metric, such as one with units of temperature, to describe thermal denaturation of collagen. Comparing the results of studies that measured denaturation and cell death for a variety of biological samples shows that the parameters for either the Arrhenius equation (i.e. activation energy Ea and the frequency factor A) appear correlated over the range of temperatures for which biological materials are tested [4]. It has also been suggested that denaturation is a first-order phase change (i.e., melting) and thus should be characterized by a melting or denaturation temperature Td [5].

scholarly journals Kinetics of the activation of rat liver pyruvate kinase by fructose 1,6-disphosphate and methods for characterizing hysteretic transitions

1974 ◽  
Vol 141 (1) ◽  
pp. 119-125 ◽  
Author(s):  
H. Olin Spivey ◽  
Wayne Flory ◽  
Benigno D. Peczon ◽  
John P. Chandler ◽  
Roger E. Koeppe
Keyword(s):  
Pyruvate Kinase ◽  
Active Form ◽  
Enzyme Concentration ◽  
Type I ◽  
Numerical Techniques ◽  
First Order ◽  
First Order Transition ◽  
Model Equations ◽  
Kinetics Of ◽  
Increasing Function

1. Kinetics of fructose 1,6-diphosphate activation of liver pyruvate kinase type I inhibited with MgATP and l-alanine are described as a function of enzyme and fructose 1,6-diphosphate concentrations. These results can be explained by a single pseudo-first-order transition of the enzyme into an active form, independent of the enzyme concentration. This rate constant, kapp.=0.24s-1 with 0.02mm-fructose 1,6-diphosphate (t0.9 ≃ 10s where t0.9 is the time for 90% conversion), is an increasing function of fructose 1,6-diphosphate concentration far beyond that needed to maximally activate enzyme equilibrated with fructose 1,6-diphosphate (about 20μm). 2. The model equations are best analysed with numerical techniques which are described. These techniques are useful in studying similar slow transients frequently observed in stopped-flow studies of enzymes. 3. Shorter transients (t0.9=0.5–1.5s) were observed in the kinetic response of the enzyme to the addition of MgATP or phosphoenolpyruvate, but were not further characterized.

Kinetic of oxidation of methyl orange by vanadium(V) under conditions VO2+ and decavanadates coexist: Catalysis by Triton X-100 micellar medium

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Methyl Orange ◽  
Solution Ph ◽  
Vanadium Concentration ◽  
Limiting Behavior ◽  
First Order ◽  
First Order Kinetics ◽  
Ph Range ◽  
Kinetic Pattern ◽  
Triton X ◽  
Kinetics Of

The kinetics of oxidation of methyl orange by vanadium(V) {V(V)} has been investigated in the pH range 2.3-3.79. In this pH range V(V) exists both in the form of decavanadates and VO2+. The kinetic results are distinctly different from the results obtained for the same reaction in highly acidic solution (pH < 1) where V(V) exists only in the form of VO2+. The reaction obeys first order kinetics with respect to methyl orange but the rate has very little dependence on total vanadium concentration. The reaction is accelerated by H+ ion but the dependence of rate on [H+] is less than that corresponding to first order dependence. The equilibrium between decavanadates and VO2+ explains the different kinetic pattern observed in this pH range. The reaction is markedly accelerated by Triton X-100 micelles. The rate-[surfactant] profile shows a limiting behavior indicative of a unimolecular pathway in the micellar pseudophase.

The Kinetics of Glucose Decomposition with Sulfate Reduction in the Anaerobic Fluidized Bed Reactor

1993 ◽  
Vol 28 (2) ◽  
pp. 135-144 ◽  
Author(s):  
S. Matsui ◽  
R. Ikemoto Yamamoto ◽  
Y. Tsuchiya ◽  
B. Inanc
Keyword(s):  
Sulfate Reduction ◽  
Fluidized Bed ◽  
Kinetic Equations ◽  
Fluidized Bed Reactor ◽  
Order Reaction ◽  
First Order Reaction ◽  
First Order ◽  
Glucose Decomposition ◽  
Reaction Equations ◽  
Kinetics Of

Using a fluidized bed reactor, experiments on glucose decomposition with and without sulfate reduction were conducted. Glucose in the reactor was mainly decomposed into lactate and ethanol. Lactate was mainly decomposed into propionate and acetate, while ethanol was decomposed into propionate, acetate, and hydrogen. Sulfate reduction was not involved in the decomposition of glucose, lactate, and ethanol, but was related to propionate and acetate decomposition. The stepwise reactions were modeled using either a Monod expression or first order reaction kinetics in respect to the reactions. The coefficients of the kinetic equations were determined experimentally. The modified Monod and first order reaction equations were effective at predicting concentrations of glucose, lactate, ethanol, propionate, acetate, and sulfate along the beight of the reactor. With sulfate reduction, propionate was decomposed into acetate, while without sulfate reduction, accumulation of propionate was observed in the reactor. Sulfate reduction accelerated propionate conversion into acetate by decreasing the hydrogen concentration.

Submerged upflow biotower operation and computer simulation

1994 ◽  
Vol 30 (11) ◽  
pp. 143-146
Author(s):  
Ronald D. Neufeld ◽  
Christopher A. Badali ◽  
Dennis Powers ◽  
Christopher Carson
Keyword(s):  
Computer Simulation ◽  
Benzoic Acid ◽  
Computer Model ◽  
Rate Constants ◽  
Batch Mode ◽  
Operational Conditions ◽  
First Order ◽  
Low Concentrations ◽  
Biological Transformation ◽  
Kinetics Of

A two step operation is proposed for the biodegradation of low concentrations (< 10 mg/L) of BETX substances in an up flow submerged biotower configuration. Step 1 involves growth of a lush biofilm using benzoic acid in a batch mode. Step 2 involves a longer term biological transformation of BETX. Kinetics of biotransformations are modeled using first order assumptions, with rate constants being a function of benzoic acid dosages used in Step 1. A calibrated computer model is developed and presented to predict the degree of transformation and biomass level throughout the tower under a variety of inlet and design operational conditions.

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