Effects of organic solvents on immobilized enzyme catalyses. Chymotrypsin immobilized on Sephadex

1980 ◽  
Vol 58 (23) ◽  
pp. 2633-2640 ◽  
Author(s):  
Diana H. Pliura ◽  
J. Bryan Jones
Keyword(s):  
Enzyme Activity ◽  
Organic Solvents ◽  
Immobilized Enzyme ◽  
Reaction Medium ◽  
Butyl Alcohol ◽  
Native Enzyme ◽  
Tert Butyl ◽  
Tert Butyl Alcohol ◽  
Catalytic Rate ◽  
Hydrolysis Of

The esterolytic activities of native chymotrypsin (CT) and immobilized CT-Sephadex have been studied in the presence of up to 20% of the organic solvents methanol, ethanol, 2-propanol, tert-butyl alcohol, dioxane, or DMSO. The general cosolvent-induced inhibition of the native enzyme was attenuated for immobilized CT. Most noticeably, the apparent catalytic rate constants for the CT-Sephadex-catalyzed hydrolysis of N-acetyl-L-tyrosine ethyl ester were invariant over the 2–20% dioxane concentration range surveyed. In contrast, the activity of the native enzyme in 20% dioxane was only 3% the activity recorded in the absence of cosolvent. Increasing the hydrophobic character of the protic cosolvents destabilized the native enzyme but stabilized CT-Sephadex. Both native and immobilized CT displayed remarkable stability in 20% aqueous DMSO [Formula: see text]. At least part of the DMSO-induced inhibition of native CT and CT-Sephadex was offset by increasing the apparent pH of the reaction medium. The altered kinetic patterns for CT-Sephadex are best explained by the effects of diffusional limitations on the apparent enzyme activity. The best compromise solvent for preparative applications of CT-Sephadex was found to be tert-butyl alcohol.

Kinetics and mechanism of hydrolysis of substituted phenyl N-(4-methylphenyl)sulphonylcarbamates. Solvolysis of 3-nitrophenyl N-(4-methylphenyl)-sulphonylcarbamate in mixtures water-1,4-dioxane and water-tert-butyl alcohol and its decomposition to neutral molecules in non-aqueous media

1979 ◽  
Vol 44 (9) ◽  
pp. 2639-2652 ◽  
Author(s):  
Jitka Moravcová ◽  
Miroslav Večeřa
Keyword(s):  
Organic Solvents ◽  
Ph Dependence ◽  
Aqueous Media ◽  
Activation Parameters ◽  
Butyl Alcohol ◽  
Base Catalysis ◽  
Hydrolysis Rate ◽  
Tert Butyl ◽  
Tert Butyl Alcohol ◽  
Hydrolysis Of

pH Dependence of hydrolysis rate of the substituted phenyl N-(4-methylphenyl)sulphonylcarbamates has been followed in aqueous medium. The activation parameters and the Hammet reaction constant (ρ = 2.4) have been determined at pH 11.3. For hydrolysis of 3-nitrophenyl N-(4-methylphenyl)sulphonylcarbamate (pK about 3.5) no general base catalysis has been found. The hydrolysis mechanism is discussed. Perturbation of the water structure by organic solvents (1,4-dioxane and tert-butyl alcohol) has been used for differentiation of ElcB and Bac2 mechanisms, 2,4-dinitrophenyl acetate being used for comparison. The decomposition rates of 3-nitrophenyl N(4-methylphenyl)sulphonylcarbamate have been determined in six organic solvents. Mechanism of spontaneous splitting of the carbamate molecule in non-aqueous media is discussed.

Effects of organic solvents on immobilized enzyme catalyses. Chymotrypsin immobilized on porous glass

1981 ◽  
Vol 59 (19) ◽  
pp. 2921-2925 ◽  
Author(s):  
J. Bryan Jones ◽  
Diana H. Pliura
Keyword(s):  
Organic Solvent ◽  
Organic Solvents ◽  
Porous Glass ◽  
Immobilized Enzyme ◽  
Butyl Alcohol ◽  
Solvent Concentration ◽  
Marked Contrast ◽  
Practical Applications ◽  
Tert Butyl Alcohol ◽  
Esterolytic Activity

The esterolytic activity of native chymotrypsin (CT) immobilized on ionically neutral porous glass beads has been studied in the presence of up to 20% (v/v) of the organic solvents methanol, ethanol, 2-propanol, tert-butyl alcohol, dioxane, and DMSO. In marked contrast to the variations observed with native CT, inhibition of CT immobilized on glass (CT–glass) was independent of the nature of the organic solvent. The overall activity, as indicated by kc(app)/km(app), decreased by 35–50% as the concentration of all solvents surveyed was increased up to 20%. In general, high organic solvent concentration accelerated the rate of protein release from the insoluble catalyst. For practical applications in aqueous organic solvents CT–glass conjugates are inferior to those of the enzyme attached to Sephadex.

Coefficients B de viscosité dans les systèmes ternaires aqueux. III. Halogénures alcalins–alcool tert-butylique–eau à 25 °C

1979 ◽  
Vol 57 (24) ◽  
pp. 3247-3252 ◽  
Author(s):  
Marc Palma ◽  
Jean-Pierre Morel
Keyword(s):  
Linear Relationship ◽  
Structural Properties ◽  
Organic Solvents ◽  
Linear Correlation ◽  
Butyl Alcohol ◽  
Tert Butyl ◽  
Tert Butyl Alcohol ◽  
Alcohol Water ◽  
Coefficient Of Viscosity

We have measured the coefficient of viscosity B at 25 °C of HCl, LiCl, NaCl, KCl, RbCl, KI, and KBr in the mixtures of aqueous organic solvents containing from 10 to 40% tert-butyl alcohol by weight (X), the concentration of electrolyte varying from 0.1 to 0.3 M.Plots of B = f (x) show points of inflexion and minima whose positions can be explained by the structural properties of the mixed solvent.In water, a linear relationship between the entropy of hydration and coefficient B of the ions is observed. In the same way, it can be shown that a linear correlation exists between the entropy of solvation and coefficient B of the electrolytes for all the mixtures studied.These correlations lead to the characterization of two distinct zones (X < 20% and X > 20%) for the range of tert-butyl alcohol–water mixtures. [Journal translation]

Medium effect on alkaline hydrolysis of diphenic acid monomethyl ester

1980 ◽  
Vol 45 (5) ◽  
pp. 1485-1494 ◽  
Author(s):  
Ján Benko ◽  
Vladislav Holba
Keyword(s):  
Alkaline Hydrolysis ◽  
Reaction Medium ◽  
Activation Parameters ◽  
Butyl Alcohol ◽  
Medium Effect ◽  
Tert Butyl Alcohol ◽  
Diphenic Acid ◽  
Different Temperatures ◽  
Hydrolysis Of ◽  
Monomethyl Ester

The alkaline hydrolysis of diphenic acid monomethyl ester was studied in mixtures of water with methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, tert-butyl alcohol, and acetone. The dependences of the rate constant on the concentration of the nonaqueous component at different temperatures were obtained and the activation parameters at an isodielectric composition of the reaction medium were determined. The influence of the ionic strength on the reaction rate in the mentioned media was studied and conclusions were drawn as to the role of specific interactions between the reacting ions in the kinetics and mechanism of the studied reaction.

Thermodynamic and Kinetic Investigation of the Solvent Effect on the Oxidation of [Co(en)2SCH2COO]+ with S2O82- In Water-Methanol and Water-tert-Butyl Alcohol Mixtures

1993 ◽  
Vol 58 (5) ◽  
pp. 1001-1006 ◽  
Author(s):  
Oľga Vollárová ◽  
Ján Benko
Keyword(s):  
Transfer Functions ◽  
Activation Parameters ◽  
Butyl Alcohol ◽  
Oxidation Of Co ◽  
Kinetics Of Oxidation ◽  
Tert Butyl ◽  
Tert Butyl Alcohol ◽  
Alcohol Mixtures ◽  
Kinetics Of

The kinetics of oxidation of [Co(en)2SCH2COO]+ with S2O82- was studied in water-methanol and water-tert-butyl alcohol mixtures. Changes in the reaction activation parameters ∆H≠ and ∆S≠ with varying concentration of the co-solvent depend on the kind of the latter, which points to a significant role of salvation effects. The solvation effect on the reaction is discussed based on a comparison of the transfer functions ∆Ht0, ∆St0 and ∆Gt0 for the initial and transition states with the changes in the activation parameters accompanying changes in the CO-solvent concentration. The transfer enthalpies of the reactant were obtained from calorimetric measurements.

scholarly journals Impacts of Sn(II) doping on the Keggin heteropolyacid-catalyzed etherification of glycerol with tert-butyl alcohol

2021 ◽  
pp. 116913
Author(s):  
Márcio José da Silva ◽  
Diego Morais Chaves ◽  
Sukarno Olavo ferreira ◽  
Rene Chagas da Silva ◽  
Jose Balena Gabriel Filho ◽  
...  
Keyword(s):  
Butyl Alcohol ◽  
Tert Butyl ◽  
Tert Butyl Alcohol
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