scholarly journals A kinetic analysis of enzyme systems involving four substrates

1974 ◽  
Vol 141 (3) ◽  
pp. 789-805 ◽  
Author(s):  
Keith R. F. Elliott ◽  
Keith F. Tipton
Keyword(s):  
Kinetic Analysis ◽  
Kinetic Data ◽  
Initial Rate ◽  
Product Inhibition ◽  
Rate Equations ◽  
Enzyme Mechanisms ◽  
Enzyme Systems

A treatment of kinetic data for enzyme mechanisms involving four substrates is described. The initial-rate equations and product-inhibition patterns for such mechanisms are presented. The treatment is extended to include analysis of enzyme mechanisms involving three substrates in which two molecules of one substrate are used.

scholarly journals The interpretation of kinetic data for enzyme-catalysed reactions involving three substrates

1969 ◽  
Vol 114 (3) ◽  
pp. 547-556 ◽  
Author(s):  
K. Dalziel
Keyword(s):  
Kinetic Data ◽  
Initial Rate ◽  
Rate Equations ◽  
Rate Data ◽  
Designed Experiments

The analysis and interpretation of initial-rate data for reactions involving three substrates, obtained in suitably designed experiments, are discussed. Possible mechanisms for such reactions are classified, the rate equations are compared and the extent to which they can be distinguished experimentally is considered.

scholarly journals The quantitative analysis of ligand binding and initial-rate data for allosteric and other complex enzyme mechanisms

1976 ◽  
Vol 153 (1) ◽  
pp. 101-117 ◽  
Author(s):  
W G Bardsley
Keyword(s):  
Kinetic Data ◽  
Quantitative Data ◽  
Initial Rate ◽  
Graphical Methods ◽  
Enzyme Kinetic ◽  
Rate Data ◽  
Curve Shape ◽  
High Substrate Concentration ◽  
Complex Curve ◽  
Complex Curves

1. The eight methods for plotting enzyme kinetic data are classified and analysed, and it is shown how, in each case, it is only possible to obtain quantitative data on the coefficients of the lowest- and highest-degree terms in the rate equation. 2. The combinations of coefficients that are accessible experimentally from limiting slopes and intercepts at both low and high substrate concentration are stated for all the graphical methods and the precise effects of these on curve shape in different spaces is discussed. 3. Ambiguities arising in the analysis of complex curves and certain special features are also investigated. 4. Four special ordering functions are defined and investigated and it is shown how knowledge of these allows a complete description of all possible complex curve shapes.

Ammonium transport by the colonic H+-K+-ATPase expressed in Xenopusoocytes

1999 ◽  
Vol 277 (2) ◽  
pp. C280-C287 ◽  
Author(s):  
Marc Cougnon ◽  
Patrice Bouyer ◽  
Frédéric Jaisser ◽  
Aleksander Edelman ◽  
Gabrielle Planelles
Keyword(s):  
Kinetic Analysis ◽  
Initial Rate ◽  
Functional Expression ◽  
Competitive Inhibitor ◽  
Ammonium Transport ◽  
Xenopus Laevis Oocytes ◽  
Intracellular Acidification ◽  
Extracellular Medium ◽  
Α Subunit ◽  
External Site

Functional expression of the rat colonic H+-K+-ATPase was obtained by coexpressing its catalytic α-subunit and the β1-subunit of the Na+-K+-ATPase in Xenopus laevis oocytes. We observed that, in oocytes expressing the rat colonic H+-K+-ATPase but not in control oocytes (expressing β1 alone), NH4Cl induced a decrease in86Rb uptake and the initial rate of intracellular acidification induced by extracellular NH4Cl was enhanced, consistent with [Formula: see text] influx via the colonic H+-K+-ATPase. In the absence of extracellular K+, only oocytes expressing the colonic H+-K+-ATPase were able to acidify an extracellular medium supplemented with NH4Cl. In the absence of extracellular K+ and in the presence of extracellular [Formula: see text], intracellular Na+ activity in oocytes expressing the colonic H+-K+-ATPase was lower than that in control oocytes. A kinetic analysis of86Rb uptake suggests that[Formula: see text] acts as a competitive inhibitor of the pump. Taken together, these results are consistent with[Formula: see text] competition for K+ on the external site of the colonic H+-K+-ATPase and with [Formula: see text] transport mediated by this pump.

Derivation of Initial Rate Equations for Low-temperature Water Gas Shift Reaction over Pt–Re/ZrO2Catalysts

2010 ◽  
Vol 39 (2) ◽  
pp. 144-145 ◽  
Author(s):  
Hajime Iida ◽  
Takumi Yamamoto ◽  
Masaru Inagaki ◽  
Akira Igarashi
Keyword(s):  
Low Temperature ◽  
Initial Rate ◽  
Water Gas Shift ◽  
Rate Equations ◽  
Water Gas Shift Reaction ◽  
Shift Reaction ◽  
Water Gas ◽  
Temperature Water

Deriving the rate equations for product inhibition patterns in bisubstrate enzyme reactions

2006 ◽  
Vol 21 (6) ◽  
pp. 617-634 ◽  
Author(s):  
Vladimir Leskovac ◽  
Svetlana Trivić ◽  
Draginja Peričin ◽  
Julijan Kandrač
Keyword(s):  
Product Inhibition ◽  
Rate Equations ◽  
Enzyme Reactions

scholarly journals Integrated rate equations for enzyme-catalysed first-order and second-order reactions

1984 ◽  
Vol 223 (1) ◽  
pp. 15-22 ◽  
Author(s):  
E A Boeker
Keyword(s):  
Initial Rate ◽  
Second Order ◽  
Rate Equations ◽  
First Order ◽  
Rate Kinetics

Generalized rate equations covering all mechanisms giving hyperbolic initial-rate kinetics with stoichiometry A in equilibrium P, A in equilibrium P + Q, A + B in equilibrium P and A + B in equilibrium P + Q were integrated. The results are regular and reasonably economical.

KINETIC STUDIES ON THE MECHANISM OF CYTOPLASMIC L-α-GLYCEROPHOSPHATE DEHYDROGENASE OF RABBIT SKELETAL MUSCLE

1966 ◽  
Vol 44 (10) ◽  
pp. 1301-1317 ◽  
Author(s):  
William J. Black
Keyword(s):  
Kinetic Data ◽  
Substrate Inhibition ◽  
Product Inhibition ◽  
Reduced Form ◽  
Ultraviolet Absorption Spectrum ◽  
Dihydroxyacetone Phosphate ◽  
Enzyme Complex ◽  
Rabbit Muscle ◽  
Glycerophosphate Dehydrogenase ◽  
Dead End

Studies on initial velocity and product inhibition were carried out on crystalline cytoplasmic NAD+-linked L-α-glycerophosphate dehydrogenase from rabbit muscle, at pH 7.8 and 9.0 at 26 °C. Michaelis and inhibition constants for all the reactants were determined. The kinetic data were consistent with an ordered mechanism in which nicotinamide–adenine dinucleotide (NAD+) or its reduced form (NADH) is bound to the enzyme before the addition of the glycerophosphate (LαGP) or dihydroxyacetone phosphate (DHAP) respectively. At high concentrations NADH, DHAP, and LαGP, but not NAD+, produced substrate inhibition. Combined product-inhibition and dead-end inhibition studies indicated the formation of inactive dead-end complexes of NADH–enzyme, DHAP–enzyme, and LαGP–enzyme–NADH. The low rate constant calculated for the dissociation of the active NADH–enzyme complex suggested an ordered mechanism involving either the formation of an inactive dead-end NADH–enzyme complex or an isomerized NADH–enzyme complex. A choice between these possibilities could not be made on the basis of the present kinetic data. A mechanism for substrate inhibition involving two NAD+-binding sites per mole of enzyme is proposed. Alterations of the ultraviolet absorption spectrum of the enzyme by NAD+ and NADH were in agreement with the conclusion from the kinetic results that the coenzymes are bound to the enzyme before the substrates. DHAP and LαGP caused no alteration in the enzyme spectrum. Spectral changes compatible with the formation of ternary and dead-end complexes were also detected.

scholarly journals Purification and kinetic properties of ox brain histamine N-methyltransferase

1986 ◽  
Vol 233 (3) ◽  
pp. 669-676 ◽  
Author(s):  
W L Gitomer ◽  
K F Tipton
Keyword(s):  
Acetic Acid ◽  
Steady State ◽  
Mouse Brain ◽  
Initial Rate ◽  
Substrate Inhibition ◽  
Gel Filtration ◽  
Product Inhibition ◽  
Kinetic Properties ◽  
Brain Histamine ◽  
Inhibition Studies

Histamine N-methyltransferase (EC 2.1.1.8) was purified 1100-fold from ox brain. The native enzyme has an Mr of 34800 +/- 2400 as measured by gel filtration on Sephadex G-100. The enzyme is highly specific for histamine. It does not methylate noradrenaline, adrenaline, DL-3,4-dihydroxymandelic acid, 3,4-dihydroxyphenylacetic acid, 3-hydroxytyramine or imidazole-4-acetic acid. Unlike the enzyme from rat and mouse brain, ox brain histamine N-methyltransferase did not exhibit substrate inhibition by histamine. Initial rate and product inhibition studies were consistent with an ordered steady-state mechanism with S-adenosylmethionine being the first substrate to bind to the enzyme and N-methylhistamine being the first product to dissociate.

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