scholarly journals KINETICS OF THE BIOLUMINESCENT REACTION IN CYPRIDINA. II

1922 ◽  
Vol 4 (5) ◽  
pp. 535-558 ◽  
Author(s):  
William R. Amberson
Keyword(s):  
Heterogeneous System ◽  
Decay Curve ◽  
Enzyme Concentration ◽  
Complete Agreement ◽  
Theoretical Expectation ◽  
Reaction Velocity ◽  
Monomolecular Reaction ◽  
Straight Line ◽  
Experimental Values ◽  
Kinetics Of

1. The decay curve of the light produced in the course of the luminescent reaction in Cypridina is, after the first second, in complete agreement with the theoretical expectation for a monomolecular reaction, if light intensity at any instant is assumed to be proportional to reaction velocity at that instant. It is shown that for such a reaction log I = - kt + log Ak and that the experimental values satisfy this equation. 2. The first second or two of the reaction is characterized by a brilliant initial flash, whose value is much too high to accord with the succeeding intensities and with the above formula. It is suggested that this initial high reaction velocity is an indication of a heterogeneous system. 3. Identical solutions run simultaneously give decay curves which check within the limits of the photographic error. 4. Stirring does not affect the reaction velocity or the form of the decay curve. 5. Reaction velocity is proportional to enzyme concentration, over the range of concentrations used in the study. 6. Changes in the concentration of the substrate do not affect the value of k, when all other factors are held constant. A diminution of luciferin concentration results only in a decrease in the value of the y-intercept, Log Ak, the two straight line plottings for two different concentrations being parallel. 7. The temperature coefficient is high, being about 4.5 for the 15–25° interval, and 3.0 for the 25–35° interval.

scholarly journals Kinetics of Enzymatic Hydrolysis of Southeast Sulawesi Sago Starch

2020 ◽  
pp. 53-61
Author(s):  
Ansharullah Ansharullah ◽  
Muhammad Natsir
Keyword(s):  
Enzymatic Hydrolysis ◽  
Maximum Velocity ◽  
Enzyme Concentration ◽  
Hydrolysis Rate ◽  
Sago Starch ◽  
Optimum Conditions ◽  
Kinetics Of ◽  
Hydrolysis Of ◽  
Substrate Concentrations ◽  
Menten Constant

The aims of this study were to characterize the kinetics of enzymatic hydrolysis of sago starch, obtained from Southeast Sulawesi Indonesia. The enzyme used for hydrolysis was bacterial ∝-amylase (Termamyl 120L from Bacillus licheniformis, E. C. 3.2.1.1).  The method to determine the initial velocity (Vo) of the hydrolysis was developed by differentiation a nonlinear equation (NLE).  The Vo of the hydrolysis was measured at various pH (6.0, 6.5,and 7.0), temperatures (40, 60, 75 and 95oC), enzyme concentrations (0.5, 1.0, 1.5 and 2.0 µg per mL) and in the presence of 70 ppm Ca++. The optimum conditions of this experiment were found to be at pH 6.5 – 7.0 and 75oC, and the Vo increased with increasing enzyme concentration. The Vo values at various substrate concentrations were also determined, which were then used to calculate the enzymes kinetics constant of the hydrolysis, including Michaelis-Menten constant (Km) and maximum velocity (Vmax) using a Hanes plot.  Km and Vmax values were found to be higher in the measurement at pH 7.0 and 75oC. The Km values  at four  different combinations of pH and temperatures (pH 6.5, 40oC; pH 6.5, 75oC; pH 7.0, 40oC; pH 7.0, 75oC) were found to be 0.86, 3.23, 0.77 and 3.83 mg/mL, respectively; and Vmax values were 17.5, 54.3, 20.3 and 57.1 µg/mL/min, respectively. The results obtained showed that hydrolysis rate of this starch was somewhat low.

scholarly journals Study of the regularity of the process of decomposition of apatite with sulfuricacid at the boilingpoint of the solution

2019 ◽  
Vol 58 (4) ◽  
pp. 119-122
Author(s):  
Rauf F. Sabirov ◽  
◽  
Alexey F. Makhotkin ◽  
Yury N. Sakharov ◽  
Igor A. Makhotkin ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Phosphoric Acid ◽  
Boiling Point ◽  
Batch Reactor ◽  
Material Balance ◽  
Mercury Thermometer ◽  
Experimental Values ◽  
Kinetics Of ◽  
Liquid And Solid Phases ◽  
Phosphoric Acids

Experimental research of the kinetics of the decomposition process of Kovdorsky apatite with a size = 0.16 mm with sulfuric acid in a 1 dm3 batch reactor. Phosphoric acid with the concentration of 68.6 % wt and the sulfuric acid with the concentration of 12.3% wt in stoichiometric amount was introduces at the beginning of the process. The process was carried out at a ratio of liquid and solid phases 2.5:1 respectively at the boiling point of the mixture equal to 136 °C. The observing the progress was carried out according to the method of joint designation of sulfuric and phosphoric acids by titrimetric analysis. With methyl orange and then phenolphthalein 2 titration jumps were recorded, the first of which corresponded to the neutralization of sulfuric acid to Na2SO4 and phosphoric acid to NaH2PO4, the second to the neutralization of NaH2PO4 to Na2HPO4. The change in temperature of the reaction mixture was fixed during the process using a mercury thermometer. In the analysis of the derived experimental values of specified parameters that the boiling point decreases from 136 to 133.1 оС within 50 minutes during the process. A comparison of the reported values with the concentration values of sulfuric and phosphoric acids measured during the process shows that the change in boiling point of the reaction mixture is proportional to the change in the concentrations of sulfuric and phosphoric acids. This model is a closed system that provides thermal insulation and no loss of material balance. Thus, the kinetics of the decomposition of apatite with sulfuric acid at the boiling point can be monitored by the temperature change under specified conditions.

scholarly journals Effect of the MgO/Silica Fume Ratio on the Reaction Process of the MgO–SiO2–H2O System

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 80 ◽  
Author(s):  
Zhaoheng Li ◽  
Yudong Xu ◽  
Hao Liu ◽  
Jianwei Zhang ◽  
Jiangxiong Wei ◽  
...  
Keyword(s):  
Reaction Kinetics ◽  
Silica Fume ◽  
Main Product ◽  
Magnesium Silicate ◽  
Reaction Process ◽  
Reaction Products ◽  
Degree Of Reaction ◽  
Reaction Thermodynamics ◽  
Experimental Values ◽  
Kinetics Of

In order to clarify the effect of the MgO–silica fume (SF) ratio on the reaction process of the MgO–SiO2–H2O system, the reaction products and degree of reaction were characterized. Furthermore, the parameters of the reaction thermodynamics were calculated and the reaction kinetics were deduced. The results indicate that a large amount of Mg(OH)2 and small quantities of magnesium silicate hydrate (M–S–H) gels were generated upon dissolution of MgO. However, the M–S–H gels were continuously generated until the SF or Mg(OH)2 was consumed completely. For a MgO dosage less than 50% of the total MgO–SiO2–H2O system, the main product was M–S–H gel, while for a MgO dosage greater than 50%, the main product was Mg(OH)2. The results indicate that M–S–H gels have greater stability than Mg(OH)2, and the final reaction product was prone to be M–S–H gels. Based on the experimental values, an equation is proposed for the reaction kinetics of MgO.

Kinetics of the Back Reaction of Photosystem II as Derived from Delayed Light Emission in the Presence of DCMU and the Conformational State of the Thylakoid Membrane

1980 ◽  
Vol 35 (7-8) ◽  
pp. 638-644 ◽  
Author(s):  
Gerhard Vierke
Keyword(s):  
Photosystem Ii ◽  
Light Emission ◽  
Decay Curve ◽  
Conformational State ◽  
Time Range ◽  
Back Reaction ◽  
Luminescence Decay Curve ◽  
Photosynthetic Membrane ◽  
Internal Ph ◽  
Kinetics Of

Abstract It is shown that the kinetics of the back reaction of photosystem II in the seconds time range as derived from the luminescence decay curve in the presence of DCMU is controlled by the internal pH of the thylakoids. Modifications of the conformational state of the photosynthetic membrane while leaving the internal pH unchanged, however, reaction.

THE KINETICS OF CUPRENE GROWTH

1950 ◽  
Vol 28b (7) ◽  
pp. 358-372
Author(s):  
Cyrias Ouellet ◽  
Adrien E. Léger
Keyword(s):  
Nitric Oxide ◽  
Activation Energy ◽  
Carbon Monoxide ◽  
Apparent Activation Energy ◽  
Copper Catalyst ◽  
Maximum Velocity ◽  
Static System ◽  
Reaction Velocity ◽  
First Order ◽  
Kinetics Of

The kinetics of the polymerization of acetylene to cuprene on a copper catalyst between 200° and 300 °C. have been studied manometrically in a static system. The maximum velocity of the autocatalytic reaction shows a first-order dependence upon acetylene pressure. The reaction is retarded in the presence of small amounts of oxygen but accelerated by preoxidation of the catalyst. The apparent activation energy, of about 10 kcal. per mole for cuprene growth between 210° and 280 °C., changes to about 40 kcal. per mole above 280 °C. at which temperature a second reaction seems to set in. Hydrogen, carbon monoxide, or nitric oxide has no effect on the reaction velocity. Series of five successive seedings have been obtained with cuprene originally grown on cuprite, and show an effect of aging of the cuprene.

scholarly journals Effect of Cationic/Anionic Mixed Micelles on Reaction Kinetics of Alkaline Hydrolysis of Crystal Violet

2019 ◽  
Vol 31 (3) ◽  
pp. 651-655
Author(s):  
Qidist Yilma ◽  
Dunkana Negussa ◽  
Y. Dominic Ravichandran
Keyword(s):  
Crystal Violet ◽  
Alkaline Hydrolysis ◽  
Mixed Micelles ◽  
Sodium Dodecyl ◽  
Binding Constants ◽  
Regression Parameters ◽  
Experimental Values ◽  
Kinetics Of ◽  
Hydrolysis Of ◽  
Good Agreement

Kinetics of alkaline hydrolysis of crystal violet, a triphenylmethane dye in the micellar environment of cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulfonate (SDS) and binary mixtures of these surfactants was studied. The regression parameters, together with rate constants and binding constants were obtained by analyzing the rate surfactant profiles using cooperativity model. It was observed that the reaction was catalyzed by both surfactants. The catalytic factor increased by 10 times in SDS and 38 times in CTAB indicating that binding of crystal violet to the micellar surface is stronger in pure CTAB than SDS but the strength drastically reduced in the mixtures of the surfactants. Reduction of binding constant became more important as the mole fraction of CTAB was improved in the mixture. The kinetic data were investigated using Piszkiewicz model and Raghavan-Srinivasan model. The data obtained from the models were in good agreement with the experimental values.

A new calculation of the kinetics of the renneting reaction

1988 ◽  
Vol 55 (4) ◽  
pp. 521-528 ◽  
Author(s):  
Douglas G. Dalgleish
Keyword(s):  
Molecular Weight ◽  
Surface Layer ◽  
Analytical Solution ◽  
Enzyme Concentration ◽  
Detailed Calculation ◽  
Repulsive Potential ◽  
First Order ◽  
Coagulation Process ◽  
Kinetics Of

SummaryA detailed calculation of the growth of molecular weight during the renneting of milk is given, based on a first-order breakdown of κ-casein followed by development of instability caused either by a decrease in the intermicellar repulsive potential or by the formation of holes in the stabilizing surface layer of the micelles. Unlike most of the models which have been described, this model allows a complete analytical solution. The solution is, however, complex and difficult to use simply, although it is shown that the calculations are in accord with experimental observations of the dependence of the coagulation process upon the enzyme concentration and the concentration of the milk. The calculations are also compared with those from other models of the reaction.

scholarly journals H. The Kinetics of Enzyme Cascade Systems General kinetics of enzyme cascades

1969 ◽  
Vol 173 (1032) ◽  
pp. 411-420 ◽  
Keyword(s):  
Product Formation ◽  
Coagulation Cascade ◽  
Lag Phase ◽  
Open Type ◽  
Reaction Velocity ◽  
Cascade Systems ◽  
Enzyme Cascade ◽  
Enzyme Cascades ◽  
Kinetics Of ◽  
Product Relation

The theory of the kinetics of enzyme cascades is developed. Two types of cascades are recognized, one in which the products are stable ( open cascades ) and another in which the products are broken down ( damped cascades ). It is shown that it is a characteristic of a cascade that the final product appears after a certain lag phase. After this lag phase, the velocity of product formation can be very rapid. It is shown that whereas open cascades will always show a complicated time–product relation, damped cascades can under certain circumstances resemble a simple enzymic reaction. Because the relation between the over-all reaction velocity in the extrinsic coagulation cascade and the concentration of any of the proenzymes in this cascade is a hyperbolic one, it is concluded that this cascade is of the damped type rather than the open type.

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