A Kinetic Analysis of the Fructose 1,6-Diphosphate-Activated Pyruvate Kinase from the Hepatopancreas of Carcinus maenas

1975 ◽  
Vol 3 (5) ◽  
pp. 714-716 ◽  
Author(s):  
IAN G. GILES ◽  
PETER C. POAT ◽  
KENNETH A. MUNDAY
Keyword(s):  
Kinetic Analysis ◽  
Pyruvate Kinase ◽  
Carcinus Maenas

A Kinetic Analysis of Rabbit Muscle Pyruvate Kinase in the Reverse Direction

1975 ◽  
Vol 3 (2) ◽  
pp. 312-314 ◽  
Author(s):  
IAN G. GILES ◽  
PETER C. POAT ◽  
KENNETH A. MUNDAY
Keyword(s):  
Kinetic Analysis ◽  
Pyruvate Kinase ◽  
Reverse Direction ◽  
Rabbit Muscle ◽  
Muscle Pyruvate Kinase

Substrate Inhibition of Pyruvate Kinase Isolated from the Leg Muscle of Carcinus maenas

1976 ◽  
Vol 4 (6) ◽  
pp. 1158-1160 ◽  
Author(s):  
COLIN J. NEWTON ◽  
PETER C. POAT ◽  
KENNETH A. MUNDAY
Keyword(s):  
Pyruvate Kinase ◽  
Substrate Inhibition ◽  
Carcinus Maenas ◽  
Leg Muscle

Regulation of Pyruvate Kinase from the Hepatopancreas of the Crab Carcinus maenas

1975 ◽  
Vol 3 (3) ◽  
pp. 400-402 ◽  
Author(s):  
IAN G. GILES ◽  
PETER C. POAT ◽  
KENNETH A. MUNDAY
Keyword(s):  
Pyruvate Kinase ◽  
Carcinus Maenas

L-Phenylalanine inhibition of muscle pyruvate kinase

1982 ◽  
Vol 2 (10) ◽  
pp. 825-833 ◽  
Author(s):  
T. Norman Palmer ◽  
Bhanu R. Odedra
Keyword(s):  
Skeletal Muscle ◽  
Kinetic Analysis ◽  
Pyruvate Kinase ◽  
Competitive Inhibitor ◽  
Allosteric Inhibition ◽  
Reaction Velocity ◽  
Muscle Pyruvate Kinase ◽  
Regulatory Significance

The allosteric inhibition of Ml-type pyruvate kinase from rabbit skeletal muscle by phenylalanine is reciprocally dependent on Mg2+ and phosphoenolpyruvate concentrations. At pH 8, phenylalanine acts as a competitive inhibitor with respect to Mg2+ and phosphoenolpyruvate, and vice versa. Phenylalanine introduces sigmoidicity into the dependence of the reaction velocity on [Mg2+]. In vitro kinetic analysis indicates that phenylalanine inhibition of muscle pyruvate kinase is unlikely to have regulatory significance in vivo.

scholarly journals An investigation of the interactions of the allosteric modifiers of pyruvate kinase with the enzyme from Carcinus maenas hepatopancreas

1977 ◽  
Vol 165 (1) ◽  
pp. 97-105 ◽  
Author(s):  
I G Giles ◽  
P C Poat ◽  
K A Munday
Keyword(s):  
Enzyme Activity ◽  
Pyruvate Kinase ◽  
Enzyme Preparation ◽  
Carcinus Maenas ◽  
Maximal Activity ◽  
Initial Increase ◽  
Low Concentration ◽  
Saturation Kinetics ◽  
Fructose 1,6 Bisphosphate ◽  
Allosteric Activator

1. Pyruvate kinase purified from the hepatopancrease of Carcinus maenas exhibited sigmoidal saturation kinetics with respect to the substrate phosphoenolpyruvate in the absence of the allosteric activator fructose 1,6-bisphosphate, but normal hyperbolic saturation was seen in the presence of this activator. The activation appears to be the result of a decrease in the s0.5 (phosphoenolpyruvate) and not to a change in Vmax. 2. In the presence of ADP and ATP at a constant nucleotide-pool size the results indicate that phosphoenolpyruvate co-operativity is lost on increasing the [ATP]/[ADP] ratio. 3. Paralleling this change is the observation that the fructose 1,6-bisphosphate activation became less at the [ATP]/[ATP] ratio was increased. This was due to the enzyme exhibiting a near-maximal activity in the absence of activator. 4. L-Alanine inhibited the enzyme, but homotropic co-operative interactions were only seen with a cruder (1000000g supernatant) enzyme preparation. The inhibition by alanine could be overcome by increasing the concentration of either phosphoenolpyruvate or fructose 1,6-bisphosphate, although increasing the L-alanine concentration did not appear to be able to reverse the activation by fructose 1,6-bisphosphate. 5. In the presence of a low concentration of phosphoenolpyruvate, increasing the concentration of the product, ATP, caused an initial increase in enzyme activity, followed by an inhibitory phase. In the presence of either fructose 1,6-bisphosphate or L-alanine only inhibition was seen. 6. The inhibition by ATP could not be completely reversed by fructose 1,6-bisphosphate.

A Kinetic Study of Muscle Pyruvate Kinase from Carcinus maenas

1976 ◽  
Vol 4 (3) ◽  
pp. 479-481 ◽  
Author(s):  
COLIN J. NEWTON ◽  
PETER C. POAT ◽  
KENNETH A. MUNDAY
Keyword(s):  
Kinetic Study ◽  
Pyruvate Kinase ◽  
Carcinus Maenas ◽  
Muscle Pyruvate Kinase
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