scholarly journals Effect of Mg2+ and Mn2+ on isocitrate lyase, a non-essentially metal-ion-activated enzyme. A graphical approach for the discrimination of the model for activation

1991 ◽  
Vol 276 (1) ◽  
pp. 223-230 ◽  
Author(s):  
E Giachetti ◽  
P Vanni
Keyword(s):  
Kinetic Parameters ◽  
Metal Ion ◽  
Graphical Method ◽  
Isocitrate Lyase ◽  
Enzyme Reaction ◽  
Activation Mechanism ◽  
Simple Method ◽  
Suggested Approach ◽  
Graphical Approach ◽  
Substrate Complex

We describe a simple method for the analysis of activation systems in which a metal ion modifier may combine with either the enzyme or the substrate (or both) and the metal ion-substrate complex is the true substrate of the enzyme reaction. The suggested approach is essentially a ‘graphical’ method that both provides unbiased criteria for the choice of the activation mechanism and yields good rough estimates of the kinetic parameters. The procedure, tested on a variety of simulated models, produces appropriate and reliable results. Applying this treatment to isocitrate lyase, we confirmed the data previously reported for Mg2+ [Giachetti, Pinzauti, Bonaccorsi & Vanni (1988) Eur. J. Biochem. 172, 85-92], and we found that Mn2+ functions with the same mechanism as does Mg2+, but with quite different kinetic constants. In particular, its ratio of the Vmax, values of the activated and the non-activated enzyme is less than 1, and thus Mn2+ is to be considered an inhibitor rather than an activator.

scholarly journals A graphical method for determining inhibition parameters for partial and complete inhibitors

1987 ◽  
Vol 248 (3) ◽  
pp. 815-820 ◽  
Author(s):  
M Yoshino
Keyword(s):  
Substrate Concentration ◽  
Competitive Inhibition ◽  
Graphical Method ◽  
Enzyme Reaction ◽  
Reaction Rate Constant ◽  
Inhibition Mechanism ◽  
Substrate Complex ◽  
Enzyme Substrate ◽  
Characteristic Features ◽  
Substrate Inhibitor

A new simple graphical method is described for the determination of inhibition type and kinetic parameters of an enzyme reaction without any replot. The method consists of plotting experimental data as v/(vo-v) versus the reciprocal of the inhibitor concentration at different substrate concentrations, where v and vo represent the velocity in the presence and in the absence of the inhibitor respectively with a given concentration of the substrate. Partial inhibition gives straight lines that converge on the abscissa at a point away from the origin, whereas complete inhibition gives lines that go through the origin. The inhibition constants of enzymes and the reaction rate constant of the enzyme-substrate-inhibitor complex can be calculated from the abscissa and ordinate intercepts of the plot. The relationship between the slope of the plot and the substrate concentration shows characteristic features depending on the inhibition type: for partial competitive inhibition, the straight line converging on the abscissa at-Ks, the dissociation constant of the enzyme-substrate complex; for non-competitive inhibition, a constant slope independent of the substrate concentration; for uncompetitive inhibition, a hyperbola decreasing with the increase in the substrate concentration; for mixed-type inhibition, a hyperbola increasing with the increase in the substrate concentration. The properties of the replot are useful in confirmation of the inhibition mechanism.

Estimation of Kinetic Parameters of Heterotrophic Biomass under Aerobic Conditions and Characterization of Wastewater for Activated Sludge Modelling

1992 ◽  
Vol 25 (6) ◽  
pp. 125-139 ◽  
Author(s):  
J. Kappeler ◽  
W. Gujer
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Kinetic Parameters ◽  
Specific Growth ◽  
Wastewater Treatment Plants ◽  
Simple Method ◽  
Batch Tests ◽  
Different Types ◽  
Heterotrophic Biomass

To predict the behaviour of biological wastewater treatment plants, the Activated Sludge Model No. 1 is often used. For the application of this model kinetic parameters and wastewater composition must be known. A simple method to estimate kinetic parameters of heterotrophic biomass and COD wastewater fractions is presented. With three different types of batch-tests these parameters and fractions can be determined by measuring oxygen respiration. Our measurements showed that the maximum specific growth rate µmax of heterotrophic biomass depends on temperature, reactor configuration and SRT. In typical wastewater treatment plants of Switzerland the amount of readily biodegradable substrate was generally small (about 9 % of the COD in primary effluent). The same method can also be used to determine kinetic parameters of nitrifying biomass.

scholarly journals Acidic hydrolysis of astilbin and its application for the preparation of taxifolin from Rhizoma Smilacis Glabrae

2020 ◽  
pp. 174751982094835
Author(s):  
Xiao-Lin Qiu ◽  
Qing-Feng Zhang
Keyword(s):  
Activation Energy ◽  
Kinetic Parameters ◽  
Hydrolysis Reaction ◽  
Simple Method ◽  
Acidic Hydrolysis ◽  
A Value ◽  
Hcl Concentration ◽  
Hydrolysis Of

The acidic hydrolysis of astilbin to produce its aglycone, taxifolin, was investigated in this study. The effects of aq. HCl concentration and temperature on the reaction were studied, and the kinetic parameters were calculated. The results showed that with higher aq. HCl concentration and temperature, the hydrolysis of astilbin became faster. The activation energy of the hydrolysis reaction under 1 mol L−1 aq. HCl was calculated with a value of 148.6 kJ mol−1. The reaction was successfully applied to produce taxifolin from a sample of Rhizoma Smilacis Glabrae. A simple method for the purification of taxifolin from Rhizoma Smilacis Glabrae was developed with purity of 97.5%.

Graphical evaluation of the kinetic parameters for bacterial growth

1969 ◽  
Vol 15 (10) ◽  
pp. 1201-1205 ◽  
Author(s):  
Frank E. Stratton ◽  
Perry L. McCarty
Keyword(s):  
Kinetic Parameters ◽  
Bacterial Growth ◽  
Graphical Method ◽  
Substrate Oxidation ◽  
Kinetic Rate ◽  
Substrate Use ◽  
Oxidation Curve ◽  
Estimate Rate ◽  
Rates Of Growth

Kinetic rate parameters governing the rates of growth and substrate use by bacteria may be estimated by a graphical method which makes use of the bacterial substrate oxidation curve. The method is simple and rapid and may be used to estimate rate parameters in situations in which more precise computer estimates cannot be performed.

A simple method for the determination of adsorption kinetic parameters using circulating-type shallow bed reactor (CSBR)

2017 ◽  
Vol 92 ◽  
pp. 1-8
Author(s):  
Takashi Kawakita ◽  
Huan-Jung Fan ◽  
Yoshimi Seida ◽  
Tomohiro Kinoshita ◽  
Eiji Furuya
Keyword(s):  
Kinetic Parameters ◽  
Adsorption Kinetic ◽  
Simple Method

Polarographic Study of the Electrode Reaction of Zn(II) in Formamide and Dimethylformamide

1975 ◽  
Vol 30 (5-6) ◽  
pp. 350-354 ◽  
Author(s):  
Sudhindra Swarup Sharma ◽  
Mukhtar Singh
Keyword(s):  
Kinetic Parameters ◽  
Organic Solvents ◽  
Metal Ion ◽  
Supporting Electrolyte ◽  
Electrode Reaction ◽  
Polarographic Study ◽  
Aqueous Mixtures ◽  
Diffusion Controlled ◽  
And Diffusion

The reduction of Zn(II) at the d.m.e. has been studied in aqueous mixtures of formamide and dimethylformamide. The general polarographic characteristics have been determined, using 0.1 M NaNO3 as the supporting electrolyte. The reduction of Zn(II) in these organic solvents is irreversible and diffusion controlled. The kinetic parameters, αna and kf,h have been calculated separately by KOTECKY and DELAHAY treatments. The change of polarographic characteristics and kinetic parameters is explained in terms of solvation of the metal ion in these solvents. The electrocapillary curves in the presence of these solvents have also been studied.

GLYCERIC ACID KINASE ISOLATED FROM A POLISH VARIETY OF RAPESEED (BRASSICA CAMPESTRIS L.)

1960 ◽  
Vol 38 (2) ◽  
pp. 125-134 ◽  
Author(s):  
K. Ozaki ◽  
L. R. Wetter
Keyword(s):  
Metal Ion ◽  
Brassica Campestris ◽  
Enzyme Reaction ◽  
Maximum Temperature ◽  
Glyceric Acid ◽  
Reaction Products ◽  
Ph Optimum ◽  
Stability Range ◽  
Phosphoglyceric Acid ◽  
Polish Variety

Glyceric acid kinase from Polish variety rapeseed (Brassica campestris L.) was purified approximately 30-fold by ammonium sulphate fractionation and adsorption on alumina Cγ gel. The enzyme has a pH optimum at 7.9 and a pH stability range extending from 6.5 to 7.5. The maximum temperature for the reaction was 45 °C. The phosphorylation required ATP and a metal ion; Mg++ was slightly more effective than Mn++ and Co++, while Ni++ and Zn++ were ineffective. The Michaelis constants for the Mg–ATP complex and the substrate were 7.3 × 10−4 M and 1.6 × 10−3 M respectively. The reaction products, ADP and 3-phosphoglyceric acid, inhibited the phosphorylation. Sulphydryl reagents such as p-chloromercuribenzoate, o-iodosobenzoate, N-ethylmaleimide, and iodo-acetate completely inhibited the enzyme at low concentrations. 3-Phosphoglyceric acid was isolated and characterized from the enzyme reaction mixture.

A Simple Method for Analyzing Factor IX Activation in the Patients with Hemophilia B Variants

1987 ◽  
Vol 58 (02) ◽  
pp. 705-708 ◽  
Author(s):  
Akira Yoshioka ◽  
Toshiyuki Sakai ◽  
Kazukuni Yamamoto ◽  
Yoshiaki Ohkubo ◽  
Hiromu Fukui
Keyword(s):  
Western Blotting ◽  
Time Course ◽  
Factor Ix ◽  
Hemophilia B ◽  
Activation Mechanism ◽  
Partial Purification ◽  
Simple Method ◽  
Sds Page ◽  
Time Course Study

SummaryA simple method for analyzing the activation mechanism of FIX in patients with hemophilia B variants is described. The procedure consists of rapid partial purification of FIX by BaCl2 adsorption-elution from only 3 ml of plasma, incubation with FXIa/Ca2+, SDS-PAGE, western blotting and subsequent autoradiography using monoclonal anti-FIX antibody. Abnormal FIX from the plasma of 7 unrelated patients with hemophilia BR, B+ or BM was investigated. A time course study showed that FIX in the patient with hemophilia BM (Nagoya I), BM (Nagoya II) and B Kawachinagano seemed not to be cleaved by FXIa, FIX in the patient with hemophilia B Kashihara was partially cleaved, FIX in the patient with hemophilia BM (Takatsuki) showed delayed cleavage, and that FIX in the patient with hemophilia BM (Niigata) and BM (Kiryu) was cleaved completely at a rate similar to normal FIX. These findings were identical to those previously observed for the respective factors in a purified system. The procedure used here is useful for screening for a defective activation mechanism of abnormal FIX.

Control of enzyme reaction by a designed metal-ion-dependent α-helical coiled-coil protein

2012 ◽  
Vol 17 (5) ◽  
pp. 791-799 ◽  
Author(s):  
Shigeo Murase ◽  
Sonoko Ishino ◽  
Yoshizumi Ishino ◽  
Toshiki Tanaka
Keyword(s):  
Metal Ion ◽  
Coiled Coil ◽  
Enzyme Reaction
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