scholarly journals A kinetic study of pig liver pyruvate kinase activated by fructose diphosphate

1974 ◽  
Vol 139 (3) ◽  
pp. 499-508 ◽  
Author(s):  
Neil Macfarlane ◽  
Stanley Ainsworth
Keyword(s):  
Kinetic Study ◽  
Pyruvate Kinase ◽  
Binding Sites ◽  
Experimental Results ◽  
Enzyme Complex ◽  
Pig Liver ◽  
Michaelis Constants ◽  
Inhibition Constants ◽  
Complex Forms

The paper reports a study of the reaction between phosphoenolpyruvate, ADP and Mg2+ catalysed by pig liver pyruvate kinase when activated by fructose diphosphate and K+. The experimental results are consistent with two non-sequential mechanisms in which the substrates and products of the reaction are phosphoenolpyruvate, ADP, Mg2+, pyruvate and MgATP. Pyruvate release occurs before ADP binding. Two Mg2+ ions are involved, though the two Mg2+-binding sites cannot be occupied simultaneously. An isomerized enzyme complex forms before release of MgATP. Values were determined for the Michaelis constants of the reaction. Apparent MgATP inhibition constants are also given.

scholarly journals A kinetic study of rabbit muscle pyruvate kinase

1973 ◽  
Vol 131 (2) ◽  
pp. 223-236 ◽  
Author(s):  
S. Ainsworth ◽  
N. Macfarlane
Keyword(s):  
Reaction Mechanism ◽  
Kinetic Study ◽  
Pyruvate Kinase ◽  
Random Order ◽  
Experimental Results ◽  
Rabbit Muscle ◽  
Dead End ◽  
Inhibition Constants ◽  
Muscle Pyruvate Kinase ◽  
Kinetics Of

The paper reports a study of the kinetics of the reaction between phosphoenolpyruvate, ADP and Mg2+ catalysed by rabbit muscle pyruvate kinase. The experimental results indicate that the reaction mechanism is equilibrium random-order in type, that the substrates and products are phosphoenolpyruvate, ADP, Mg2+, pyruvate and MgATP, and that dead-end complexes, between pyruvate, ADP and Mg2+, form randomly and exist in equilibrium with themselves and other substrate complexes. Values were determined for the Michaelis, dissociation and inhibition constants of the reaction and are compared with values ascertained by previous workers.

scholarly journals A kinetic study of baker's-yeast pyruvate kinase activated by fructose 1,6-diphosphate

1972 ◽  
Vol 129 (5) ◽  
pp. 1035-1047 ◽  
Author(s):  
Neil Macfarlane ◽  
Stanley Ainsworth
Keyword(s):  
Reaction Mechanism ◽  
Kinetic Study ◽  
Pyruvate Kinase ◽  
Rate Constants ◽  
Experimental Results ◽  
Phosphoryl Transfer ◽  
Dead End ◽  
Inhibition Constants ◽  
Quaternary Complex ◽  
Kinetics Of

The paper reports a study of the kinetics of the reaction between phosphoenolpyruvate, ADP and Mg2+catalysed by yeast pyruvate kinase when activated by fructose 1,6-diphosphate and K+. The experimental results indicate that the reaction mechanism is of the Ordered Tri Bi type with the substrates binding in the order phosphoenolpyruvate, ADP and Mg2+. Direct phosphoryl transfer takes place in the quaternary complex, with pyruvate released before MgATP. A dead-end enzyme–pyruvate complex is also indicated. Values have been determined for the Michaelis, dissociation and inhibition constants of the reaction. Several of the rate constants involved have also been evaluated.

scholarly journals Functional synergism in the carbohydrate-induced activation of liver-type pyruvate kinase gene expression

1995 ◽  
Vol 308 (1) ◽  
pp. 105-111 ◽  
Author(s):  
Z Liu ◽  
H C Towle
Keyword(s):  
Pyruvate Kinase ◽  
Binding Sites ◽  
Transcriptional Level ◽  
Primary Hepatocytes ◽  
Kinase Gene ◽  
Glucose Response ◽  
Hepatic Expression ◽  
Elevated Glucose ◽  
Response Prompting ◽  
Late Transcription

Hepatic expression of the liver-type pyruvate kinase (L-PK) gene is induced at the transcriptional level by increased carbohydrate metabolism in the rat. The carbohydrate response of the L-PK gene requires sequences from -171 to -124, which encompass adjacent major late transcription factor (MLTF)-like and hepatic nuclear factor (HNF)-4 binding sites. Neither site alone is capable of conferring a response, prompting us to explore the mechanism of synergy between the MLTF-like factor and HNF-4. Spacing requirements between the two factor binding sites were tested by generating a series of mutations that altered the distance between these sites. Surprisingly, all of the constructs with spacing mutations were capable of responding to elevated glucose when introduced into primary hepatocytes. Thus the glucose response does not depend on the rigid phasing of the MLTF-like and HNF-4 factors, suggesting that the factors binding to these two sites do not interact directly with each other. Substitution or inversion of the PK HNF-4 site abrogated the response to glucose and also significantly suppressed the promoter activity under non-inducing conditions. We conclude that the MLTF-like factor and HNF-4 co-operate functionally to maintain the basal activity, as well as the carbohydrate responsiveness, of the L-PK gene. A mechanism other than co-operative DNA binding is responsible for the synergism.

Supramolecular self-assemblies of inverted cucurbit[7]uril with biogenic amines

2019 ◽  
Vol 43 (1) ◽  
pp. 407-412
Author(s):  
Pei-Hui Shan ◽  
Zhi-Rui Zhang ◽  
Dong Bai ◽  
Bing Bian ◽  
Zhu Tao ◽  
...  
Keyword(s):  
Biogenic Amines ◽  
Binding Affinity ◽  
Biogenic Amine ◽  
Binding Sites ◽  
Experimental Results ◽  
Binding Interactions ◽  
Strong Binding

The binding interactions between six biogenic amine guests and the iQ[7] host were investigated. The experimental results have revealed that iQ[7] shows strong binding affinity towards five of the studied biogenic amines, but not histamine, and that the binding sites are different depending on the structure of the biogenic amine.

An autoradiographical saturation kinetic study of the different benzodiazepine binding sites in rat brain by using [3H] flunitrazepam as a radioligand

1995 ◽  
Vol 50 (10) ◽  
pp. 1619-1625 ◽  
Author(s):  
Carlos Soria ◽  
Victoria Revilla ◽  
Maria Adoración Candelas ◽  
Pedro Calvo ◽  
Arsenio Fernández-López
Keyword(s):  
Kinetic Study ◽  
Rat Brain ◽  
Binding Sites ◽  
Saturation Kinetic ◽  
Benzodiazepine Binding ◽  
Benzodiazepine Binding Sites

scholarly journals Kinetics of a self-amplifying substrate cycle: ADP–ATP cycling assay

2000 ◽  
Vol 350 (1) ◽  
pp. 237-243 ◽  
Author(s):  
Edelmira VALERO ◽  
Ramón VARÓN ◽  
Francisco GARCÍA-CARMONA
Keyword(s):  
Lactate Dehydrogenase ◽  
Kinetic Study ◽  
Pyruvate Kinase ◽  
Adenylate Kinase ◽  
Reaction Medium ◽  
Spectrophotometric Assay ◽  
Background Signal ◽  
Cyclic System ◽  
Exponential Increase ◽  
Kinetics Of

A kinetic study of an ATP–ADP amplification cyclic system involving the enzymes adenylate kinase, pyruvate kinase and l-lactate dehydrogenase has been made. The stoichiometry of the cycle is 2:1, because two molecules of ADP are synthesized from one each of ATP and AMP, and one molecule of ADP is converted back into one of ATP at each turn of the cycle. This results in a continuous exponential increase in the concentrations of ATP and ADP in the reaction medium, according to the equations obtained. This is therefore a substrate cycle that amplifies itself, the cycling rate increasing continuously with time. The background signal of the reagent was reduced by using apyrase to degrade ATP and ADP in the reagent, permitting detection limits as low as 16pmol of ATP and/or ADP in a continuous spectrophotometric assay.

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