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.

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.

scholarly journals Kinetic and regulatory properties of cytosolic pyruvate kinase from germinating castor oil seeds

1991 ◽  
Vol 279 (2) ◽  
pp. 495-501 ◽  
Author(s):  
F E Podestá ◽  
W C Plaxton
Keyword(s):  
Pyruvate Kinase ◽  
Castor Oil ◽  
Mixed Type ◽  
Competitive Inhibition ◽  
Ricinus Communis ◽  
Cytosolic Ph ◽  
Oil Seeds ◽  
Saturation Kinetics ◽  
Regulatory Properties

The kinetic and regulatory properties of cytosolic pyruvate kinase (PKc) isolated from endosperm of germinating castor oil seeds (Ricinus communis L.) have been studied. Optimal efficiency in substrate utilization (in terms of Vmax/Km for phosphoenolpyruvate or ADP) occurred between pH 6.7 and 7.4. Enzyme activity was absolutely dependent on the presence of a bivalent and a univalent metal cation, with Mg2+ and K+ fulfilling this requirement. Mg2+ binding showed positive and negative co-operativity at pH 6.5 (h = 1.6) and pH 7.2 (h = 0.69) respectively. Hyperbolic saturation kinetics were observed with phosphoenolpyruvate (PEP) and K+, whereas ADP acted as a mixed-type inhibitor over 1 mM. Glycerol (10%, v/v) increased the S0.5(ADP) 2.3-fold and altered the pattern of nucleotide binding from hyperbolic (h = 1.0) to sigmoidal (h = 1.79) without modifying PEP saturation kinetics. No activators were identified. ATP, AMP, isocitrate, 2-oxoglutarate, malate, 2-phosphoglycerate, 2,3-bisphosphoglycerate, 3-phosphoglycerate, glycerol 3-phosphate and phosphoglycolate were the most effective inhibitors. These metabolites yielded additive inhibition when tested in pairs. ATP and 3-phosphoglycerate were mixed-type inhibitors with respect to PEP, whereas competitive inhibition was observed for other inhibitors. Inhibition by malate, 2-oxoglutarate, phosphorylated triose sugars or phosphoglycolate was far more pronounced at pH 7.2 than at pH 6.5. Although 32P-labelling studies revealed that extensive phosphorylation in vivo of soluble endosperm proteins occurred between days 3 and 5 of seed germination, no alteration in the 32P-labelling pattern of 5-day-germinated endosperm was observed after 30 min of anaerobiosis. Moreover, no evidence was obtained that PKc was a phosphoprotein in aerobic or anoxic endosperms. It is proposed that endosperm PKc activity of germinating castor seeds is enhanced after anaerobiosis through concerted decreases in ATP levels, cytosolic pH and concentrations of several key inhibitors.

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.

Postnatal regulation of 2,3-DPG in sheep erythrocytes

1983 ◽  
Vol 245 (3) ◽  
pp. H506-H512
Author(s):  
P. A. Mueggler ◽  
S. Carpenter ◽  
J. A. Black
Keyword(s):  
Fetal Sheep ◽  
L Cells ◽  
Erythrocyte Concentration ◽  
Glycolytic Control ◽  
Concentration Changes ◽  
Intracellular Activities ◽  
Quantitative Changes ◽  
Glycolytic Rate ◽  
2,3 Dpg

The erythrocyte 2,3-diphosphoglycerate (2,3-DPG) concentrations of sheep change markedly during the 1st mo following birth. From measurements of erythrocyte glycolytic enzymes and intermediate concentrations, we have identified the mechanism regulating erythrocyte 2,3-DPG in postnatal sheep. The postnatal changes in erythrocyte 2,3-DPG do not result from qualitative or quantitative changes in the intracellular activities of the Rapoport-Luebering shunt enzymes, 2,3-DPG mutase or 2,3-DPG phosphatase. The postnatal 2,3-DPG changes result from changes in the erythrocyte concentration of 1,3-DPG, which is controlled by other reactions in the glycolytic pathway. Neither changes in the glycolytic control enzymes (hexokinase, phosphofructokinase, and pyruvate kinase) nor changes in the intrinsic glycolytic rate can account for these 1,3-DPG concentration changes. 1,3-DPG concentrations are regulated by the in vivo glycolytic rate, which is controlled by the intracellular concentration of glucose, the glycolytic substrate. Glucose concentrations are 0.3 mmol/l cells in erythrocytes of fetal sheep (135-140 days gestational age), increase following birth to a peak of 3.8 mmol/l cells by the 1st wk of age, and then decline to the normal adult levels of 0.5 mmol/l cells by the end of the 1st mo.

Postnatal regulation of canine oxygen delivery: control of erythrocyte 2,3-DPG levels

1982 ◽  
Vol 242 (4) ◽  
pp. H500-H506
Author(s):  
P. A. Mueggler ◽  
J. A. Black
Keyword(s):  
Pyruvate Kinase ◽  
Oxygen Affinity ◽  
Kinetic Properties ◽  
Intracellular Activity ◽  
Slow Decline ◽  
Blood Oxygen Affinity ◽  
Intracellular Concentrations ◽  
Glycolytic Rate ◽  
2,3 Dpg

The oxygen affinity of canine blood changes markedly following birth. These changes are correlated with alterations in the intracellular concentration of 2,3-diphosphoglycerate (2,3-DPG). We have examined the control of erythrocyte glycolysis by measurements of intracellular enzymes and intermediates, and we have identified the component responsible for regulation of 2,3-DPG concentration and hence blood oxygen affinity during canine postnatal development. The concentration of 2,3-DPG could be regulated entirely by the enzymes of the Rapoport-Luebering shunt. We have not detected any alterations in the levels or intracellular activity of 2,3-DPG mutase or 2,3-DPG phosphatase during development; therefore postnatal changes of 2,3-DPG must be a result of changes in the intracellular concentrations of 1,3-diphosphoglycerate (1,3-DPG) that are controlled by other reactions in the glycolytic pathway. Neither low intracellular concentrations of glucose, the glycolytic substrate, nor an inherently low glycolytic rate can account for the low 2,3-DPG levels at birth. 1,3-DPG concentrations and hence 2,3-DPG concentrations are controlled by the activity of pyruvate kinase, which acts as a glycolytic sink reaction. The intracellular activity of pyruvate kinase decreases during the first 50-60 days of age and causes the accumulation of 2,3-DPG. There is a subsequent change in the in vivo kinetic properties of the enzyme, giving increased intracellular activity and resulting in the slow decline of 2,3-DPG concentrations toward normal adult values.

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