scholarly journals Pyruvate kinases have an intrinsic and conserved decarboxylase activity

2014 ◽  
Vol 458 (2) ◽  
pp. 301-311 ◽  
Author(s):  
Wenhe Zhong ◽  
Hugh P. Morgan ◽  
Matthew W. Nowicki ◽  
Iain W. McNae ◽  
Meng Yuan ◽  
...  
Keyword(s):  
Pyruvate Kinase ◽  
Dicarboxylic Acids ◽  
Enzyme Mechanism ◽  
Decarboxylase Activity ◽  
Solution Studies ◽  
Pyruvate Kinases

We provide an enzyme mechanism for the decarboxylase activity of pyruvate kinase which is conserved from protozoa to mammals. Structural and solution studies of range of related dicarboxylic acids suggest the decarboxylase activity is restricted to oxaloacetate as a substrate.

Pyruvate kinase from the liver and kidney of Arapaima gigas

1978 ◽  
Vol 56 (4) ◽  
pp. 852-859 ◽  
Author(s):  
H. Guderley ◽  
J. H. A. Fields ◽  
J. M. Cardenas ◽  
P. W. Hochachka
Keyword(s):  
Pyruvate Kinase ◽  
Arapaima Gigas ◽  
Liver And Kidney ◽  
Low Levels ◽  
Pyruvate Kinases ◽  
Regulatory Properties ◽  
Partial Reversal

Pyruvate kinases from the kidney and liver of the osteoglossid Arapaima gigas were partially purified and characterized kinetically. The two enzymes have different elect rophoretic mobilities at pH 7.0, and while they share some qualitative similarities they show quantitative differences in their catalytic and regulatory properties. Both enzymes are activated by fructose 1.6-bisphosphate and inhibited by low levels of alanine and MgATP. The liver isozyme shows hyperbolic phosphoenolpyruvate binding, with a K1 for alanine inhibition of 0.7 mM and a K1 for MgATP inhibition of 1.0 mM. In contrast, the kidney isozyme shows cooperative phosphoenolpyruvate binding, which is accentuated at low levels of ADP. MgATP inhibition does not increase the cooperativity and shows an apparent K1 of 1.68 mM. The inhibition of alanine leads to considerable increases in the cooperativity and is effective at 1 mM and lower levels. Fructose 1.6-bisphosphate completely reverses the inhibition by alanine for both isozymes, while only leading to a partial reversal of the MgATP inhibition. These regulatory properties of both the kidney and the liver isozymes suit them for function in tissues which undergo both glycolysis and gluconeogenesis.

On the Role of Magnesium in the Reaction of the Pyruvate Kinase from Salmonella typhimurium

1986 ◽  
Vol 41 (11-12) ◽  
pp. 1018-1022
Author(s):  
Concepcion Garcia-Olalla ◽  
Amando Garrido-Pertierra
Keyword(s):  
Salmonella Typhimurium ◽  
Pyruvate Kinase ◽  
Binding Sites ◽  
Physiological Significance ◽  
Hill Coefficient ◽  
Magnesium Concentration ◽  
Pyruvate Kinases ◽  
Kinetics Of ◽  
Binding Behaviour

Abstract The kinetics of the two purified forms of pyruvate kinase from Salmonella typhimurium LT-2 were studied in assays at pH 6.8 where the relationships between the initial velocities of the catalysed reactions and Mg2+ are non-hyperbolic. The analysis show that Mg2+ display positive homotropic interactions in their binding behaviour with Hill coefficient values of 2.5 and 1.2 for the form I and II, respectively. The binding sites of the cation to the pyruvate kinases seem to be independent to those for phosphoenolpyruvate and adenosine 5′-diphosphate; changes in the magnesium concentration might be of physiological significance in relation to a rapid regeneration of adenosine 5′-triphosphate by means of the pyruvate kinase reaction.

The control of pyruvate kinases of Escherichia coli: Further studies of the enzyme activated by ribose-5-phosphate

1978 ◽  
Vol 56 (6) ◽  
pp. 647-653 ◽  
Author(s):  
John S. Mort ◽  
B. D. Sanwal
Keyword(s):  
Escherichia Coli ◽  
Pyruvate Kinase ◽  
Quaternary Structure ◽  
Native Enzyme ◽  
Open Structure ◽  
Allosteric Inhibitor ◽  
Pyruvate Kinases ◽  
Allosteric Activator

The pyruvate kinase activated by ribose-5-phosphate from Escherichia coli has been purified to homogeneity, taking advantage of the stabilization of the enzyme by its inhibitor phosphate and by thiol reagents. The native enzyme has a tetrameric quaternary structure which, while prone to dissociation under many conditions, remains intact in the presence of the above reagents.The enzyme was found to reactivate on dilution out of 8 M urea. Interestingly, the recovery of activity is greatly increased by phosphate, an allosteric inhibitor, but markedly reduced by the allosteric activator, ribose-5-phosphate, implying that it is harder for the enzyme to refold to a 'relaxed state.' Proteolysis studies indicate a more open structure in the presence of the activator.

scholarly journals The effect of temperature on catalytic and regulatory functions of pyruvate kinases of the rainbow trout and the Antarctic fish Trematomus bernacchii

1968 ◽  
Vol 110 (3) ◽  
pp. 395-400 ◽  
Author(s):  
G. N. Somero ◽  
P. W. Hochachka
Keyword(s):  
Rainbow Trout ◽  
Pyruvate Kinase ◽  
Feedback Inhibition ◽  
Antarctic Fish ◽  
Effect Of Temperature ◽  
Km Value ◽  
Trematomus Bernacchii ◽  
Regulatory Functions ◽  
Pyruvate Kinases ◽  
The Antarctic

1. The effects of temperature on the catalytic and regulatory properties of pyruvate kinases from the temperate-zone rainbow trout and the Antarctic fish Trematomus bernacchii were examined. 2. The Km value of pyruvate kinase for one of its two substrates, phosphoenolpyruvate, is temperature-dependent, and is lowest at temperatures that closely coincide with the habitat temperatures of the two fishes. 3. Two regulatory functions of pyruvate kinase, feedforward activation by fructose diphosphate and feedback inhibition by ATP, are temperature-independent. Enzyme–ADP interaction is also temperature-independent. 4. It is concluded that enzyme–substrate and enzyme–modulator interactions are important factors in short-term and in evolutionary adaptations by poikilotherms to changes in temperature. Though the Km for substrate may vary in apparently adaptive manners, the regulatory functions of an enzyme appear to be unchanged over the range of temperatures experienced by the organism in Nature.

scholarly journals Electrophoretic and Kinetic Studies of Mutant Erythrocyte Pyruvate Kinases

Blood ◽  
1974 ◽  
Vol 43 (4) ◽  
pp. 537-548 ◽  
Author(s):  
Koji Nakashima ◽  
Shiro Miwa ◽  
Susumu Oda ◽  
Takehiko Tanaka ◽  
Kiichi Imamura ◽  
...  
Keyword(s):  
Thin Layer ◽  
Pyruvate Kinase ◽  
Hemolytic Anemia ◽  
Kinetic Studies ◽  
Polyacrylamide Electrophoresis ◽  
Molecular Abnormalities ◽  
The Third ◽  
Electrophoretic Mobilities ◽  
Pyruvate Kinases ◽  
Abnormal Results

Abstract Thin-layer polyacrylamide electrophoresis and kinetic studies were used to differentiate three different mutant erythrocyte pyruvate kinase (PK) in congenital nonspherocytic hemolytic anemia. In the first family, proband and father had PK which migrated faster than the normal and high Michaelis—Menten constants (Km), whereas mother had normal migration and kinetics, but low PK activity. In the second family, proband and mother had PK which migrated slower than the normal. Proband had markedly high Km and mother intermediately high Km. In the third family, proband and mother had faster migrating PK than the normal. Proband had high Km and mother had intermediately high Km. The parents in the second and third families were consanguineous. Inherited molecular abnormalities of erythrocyte PK were proven to exist by abnormal electrophoretic mobilities, as well as abnormal results of kinetic studies.

Catalytic and regulatory properties of pyruvate kinase isozymes from octopus mantle muscle and liver

1976 ◽  
Vol 54 (6) ◽  
pp. 863-870 ◽  
Author(s):  
H. E. Guderley ◽  
K. B. Storey ◽  
J. H. A. Fields ◽  
P. W. Hochachka
Keyword(s):  
Pyruvate Kinase ◽  
Concerted Action ◽  
Mammalian Muscle ◽  
Rate Characteristic ◽  
Burst Swimming ◽  
Glycolytic Control ◽  
Slow Moving ◽  
Pyruvate Kinases ◽  
Regulatory Properties ◽  
Glycolytic Rate

The octopus is a relatively slow-moving animal that relies upon burst swimming to power its predatory activities. Pyruvate kinase (EC, 2.7.1.40), as one of the major glycolytic control sites, must be regulated in such a fashion to allow the increased glycolytic rate characteristic of burst metabolism. The mantle enzyme is regulated by the concerted action of ATP, arginine phosphate, and citrate. The Km for ADP was 0.28 mM and that for phosphoenolpyruvate (PEP), 0.25 mM. In contrast to many other invertebrate muscle pyruvate kinases, the enzyme is insensitive to fructose-1,6-diphosphate (FDP) activation.The pyruvate kinase from the liver is kinetically and electrophoretically distinct from the mantle enzyme. The liver isozyme has a considerably lower affinity for PEP (Km = 0.85 mM), is inhibited by ATP, citrate, and arginine phosphate, and is subject to a strong activation by FDP (Ka = 1 × 10−6). These differences between the pyruvate kinases from catabolic and synthetic tissues are reminiscent of the distinctions between mammalian muscle and liver pyruvate kinases.

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