pH-dependent intermediate plateaux in the kinetics of the reaction catalyzed by “biosynth” l-threonine dehydratase of Escherichia coli K-12

Kagan, Z. S.; Dorozhko, A.I.

doi:10.1016/0005-2744(73)90014-4

Cited by 16 publications

(8 citation statements)

References 14 publications

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“…(Neet and Ainslie, 1976;Banks et al, 1979;Kurganov, 1982;Nari et al, 1984;Ricard and Cornish-Bowden, 1987;Valero and Garcia-Carmona, 1992). Enzymes with similar kinetic complexities and saturation curves exhibiting various intermediate plateaus have already been reported, as in the case of L-threonine dehydratase from Escherichia coli, lactate dehydrogenase from rainbow trout muscle, and pyruvate kinase from rabbit liver (Somero and Hochachka, 1969;Williams, 1973a, 1973b;Kagan and Dorozhko, 1973). Due to the difficulty of the experimental approaches to study the membrane transport of metabolites, the existence of mnemonic kinetic behaviors has been reported only for the facilitated diffusion of adenosine in neural preparations (Casillas et al, 1993).…”

Section: Figmentioning

confidence: 87%

“…where V, VЈ, and VЉ were the transport velocities obtained at a substrate concentration of [S] 0 , [S] 0 /, and ⅐[S] 0 , respectively, and is a constant multiplier which was higher than unity, in our case the value was 2. A similar kinetic analysis was done with complex enzymatic behaviors (Kagan and Dorozhko, 1973).…”

Section: Methodsmentioning

confidence: 99%

“…Therefore, the processing of the experimental data was done by Equation 1 described under "Experimental Procedures" (Kurganov, 1982). This analytical procedure has been employed already with enzymes exhibiting similar kinetic behavior (Somero and Hochachka, 1969;Williams, 1973a, 1973b;Kagan and Dorozhko, 1973). The addition of three sigmoidal curves was necessary, in this case, to process the experimental data, as shown in Fig.…”

Section: Figmentioning

confidence: 99%

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Nucleotide Vesicular Transporter of Bovine Chromaffin Granules

Gualix

Abal

Pintor

et al. 1996

Journal of Biological Chemistry

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The nucleotide vesicular transport has been studied with the fluorescent substrate analogues, the (1,N6-ethenoadenosine) nucleotides. The transport experiments were carried out with granular preparations from bovine adrenal medulla, and epsilon-ATP, epsilon-ADP, and epsilon-AMP were quantified after separation by high performance liquid chromatography. The granular concentration increase of all three nucleotides was time-dependent. The concentration dependence of epsilon-nucleotide transport to chromaffin granules did not follow the Michaelis-Menten kinetics and presented a similar three-step curve with cooperativity. This shape can be considered to be the result of the addition of three sigmoidal curves with their corresponding kinetic parameters. epsilon-ATP exhibited K values of 0.25, 1, and 3 mM and Vmax values of 0.02, 0.04 and 0.19 nmol.min-1.mg of protein-1, for the first, second, and third curves for each step, respectively. epsilon-ADP exhibited K values of 0.15, 0.9, and 3.6 mM and Vmax values of 0.025, 0.035, and 0.3 nmol.min-1.mg of protein-1, respectively for the first, second, and third curves. epsilon-AMP exhibited K values of 0.2, 1.2, and 3.2 mM, and Vmax values of 0.01, 0.04, and 0.055 nmol.min-1.mg of protein-1, also for the first to third steps. The Hill numbers for epsilon-ATP, epsilon-ADP, and epsilon-AMP were not constant but a function of the transport saturation. The nonhydrolyzable ATP analogues AMPPNP, ATP gamma S, and ADP beta S were activators of epsilon-nucleotide transport at concentrations under 1 mM and inhibitors at higher concentrations. Atractyloside and N-ethylmaleimide partially inhibited the nucleotide granular transport. High extragranular ATP concentrations specifically induced the exit of the previously transporter granular epsilon-ATP.

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Section: Figmentioning

confidence: 87%

Section: Methodsmentioning

confidence: 99%

Section: Figmentioning

confidence: 99%

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Nucleotide Vesicular Transporter of Bovine Chromaffin Granules

Gualix

Abal

Pintor

et al. 1996

Journal of Biological Chemistry

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“…Several enzymes were identified for which two-plateau kinetics have been documented (succinate dehydrogenase [18], glutamate dehydrogenase [19], cytidine triphosphate synthetase [20], phosphoenolpyruvate carboxylase [21], pyruvate kinase [22], lactate dehydrogenase [23], acetylcholinesterase [24], L-threonine dehydratase [25]). After diaphorase the most thoroughly studied with respect to its unusual kinetics is honeybee glyceraldehyde-3-phosphate dehydrogenase [26], where an intermediate plateau is present at high but not low concentrations of substrate.…”

Section: Discussionmentioning

confidence: 99%

“…All were carefully ruled out, leaving no confirmed basis for the effect. Some reported examples show pH- [25] or temperature-dependent [22] interconversion between two-plateau and Michaelis-Menten behaviour, but no pattern is detectable that might lead to general insight into the phenomenon. Indeed, none of the reported examples has been plausibly explained in molecular terms.…”

Section: Discussionmentioning

confidence: 99%

Biphasic Kinetic Behavior of E. coli WrbA, an FMN-Dependent NAD(P)H:Quinone Oxidoreductase

et al. 2012

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The E. coli protein WrbA is an FMN-dependent NAD(P)H:quinone oxidoreductase that has been implicated in oxidative defense. Three subunits of the tetrameric enzyme contribute to each of four identical, cavernous active sites that appear to accommodate NAD(P)H or various quinones, but not simultaneously, suggesting an obligate tetramer with a ping-pong mechanism in which NAD departs before oxidized quinone binds. The present work was undertaken to evaluate these suggestions and to characterize the kinetic behavior of WrbA. Steady-state kinetics results reveal that WrbA conforms to a ping-pong mechanism with respect to the constancy of the apparent Vmax to Km ratio with substrate concentration. However, the competitive/non-competitive patterns of product inhibition, though consistent with the general class of bi-substrate reactions, do not exclude a minor contribution from additional forms of the enzyme. NMR results support the presence of additional enzyme forms. Docking and energy calculations find that electron-transfer-competent binding sites for NADH and benzoquinone present severe steric overlap, consistent with the ping-pong mechanism. Unexpectedly, plots of initial velocity as a function of either NADH or benzoquinone concentration present one or two Michaelis-Menten phases depending on the temperature at which the enzyme is held prior to assay. The effect of temperature is reversible, suggesting an intramolecular conformational process. WrbA shares these and other details of its kinetic behavior with mammalian DT-diaphorase, an FAD-dependent NAD(P)H:quinone oxidoreductase. An extensive literature review reveals several other enzymes with two-plateau kinetic plots, but in no case has a molecular explanation been elucidated. Preliminary sedimentation velocity analysis of WrbA indicates a large shift in size of the multimer with temperature, suggesting that subunit assembly coupled to substrate binding may underlie the two-plateau behavior. An additional aim of this report is to bring under wider attention the apparently widespread phenomenon of two-plateau Michaelis-Menten plots.

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Does any enzyme follow the Michaelis—Menten equation?

1977

Mol Cell Biochem

116

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A literature search has been conducted to see to what extent steady-state kinetics studies in the period 1965-1976 have revealed deviations from Michaelis-Menten kinetics. It was found that over 800 enzymes have been reported as giving complex curves for a variety of reasons and a group by group classification of all these enzymes has been carried out listing all the types of variations reported and the authors' explanations. In addition, for highly complex curves, we have determined the minimum degree of the rate equation. There were very few determined attempts to demonstrate adherence to the Michaelis-Menten equation over a wide variety of experimental conditions and substrate concentration and almost invariably detailed experimental work revealed unsuspected complexities. For these reasons, it is concluded that the assumption that most enzymes follow the Michaelis-Menten equation can not be supported by an appeal to the literature.

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pH-dependent intermediate plateaux in the kinetics of the reaction catalyzed by “biosynth” l-threonine dehydratase of Escherichia coli K-12

Cited by 16 publications

References 14 publications

Nucleotide Vesicular Transporter of Bovine Chromaffin Granules

Nucleotide Vesicular Transporter of Bovine Chromaffin Granules

Biphasic Kinetic Behavior of E. coli WrbA, an FMN-Dependent NAD(P)H:Quinone Oxidoreductase

Does any enzyme follow the Michaelis—Menten equation?

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