A study of pyruvate kinase from muscle tissue of Carcinus maenas
A study of pyruvate kinase from muscle tissue of Carcinus maenas
Pyruvate kinase was purified from the leg and pincer muscle of C. maenas, the common shore crab, to a specific actlvity of 12L units per mg of protein. The native enzyme had a molecular weight of 240,000 and a subunit molecular weight of 53,000.Although pyruvate kinase from the hepatopancreas of Cs maenas was activated by FDP aid showed a sigmoidal phosphoenolpyruvate saturation curve in the absence of FDP the muscle enzyme of this animal did not exhibit these properties and conformed in tr,i.s respect to the steady state kinetic properties of rabbit muscle pyruvate kinase.Initial rate and product inhibition studies were consistent with a rapid equilibrium mechanism in which there was a double requirement for the divalent magnesium ion for the C. maenas muscle pyruvate kinase. The steady state kinetic data could not be used to define the route of formation of the different enzyme complexes although the data was consistent with the random addition of ADP, MgADP, the magnesium ion and phosphoenolpyruvate to the (Mg-enzyme) complex.Studies of substrate inhibition by ADP and phosphoenolpyruvate at different concentrations of the free. magnesium ion suggested formation of enzyme complexesof the nature: (Mg-enzyme-MgADP-ADP), (Mg-enzyme-phosphoenolpyruvate-phosphoenolpyruvate), (Mg-enzyme-Mg-phosphoenolpyruvate-phosphoenolpyruvate) and (Mg-enzyme-MgADPphosphoenolpyruvate-phosphoenolpyruvate). The patterns obtained in the product inhibition experiments could be explained by the formation of dead-end complexes containing ADP and ATP as well as ADP and pyruvate.
University of Southampton
1977
Newton, Colin John
(1977)
A study of pyruvate kinase from muscle tissue of Carcinus maenas.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
Pyruvate kinase was purified from the leg and pincer muscle of C. maenas, the common shore crab, to a specific actlvity of 12L units per mg of protein. The native enzyme had a molecular weight of 240,000 and a subunit molecular weight of 53,000.Although pyruvate kinase from the hepatopancreas of Cs maenas was activated by FDP aid showed a sigmoidal phosphoenolpyruvate saturation curve in the absence of FDP the muscle enzyme of this animal did not exhibit these properties and conformed in tr,i.s respect to the steady state kinetic properties of rabbit muscle pyruvate kinase.Initial rate and product inhibition studies were consistent with a rapid equilibrium mechanism in which there was a double requirement for the divalent magnesium ion for the C. maenas muscle pyruvate kinase. The steady state kinetic data could not be used to define the route of formation of the different enzyme complexes although the data was consistent with the random addition of ADP, MgADP, the magnesium ion and phosphoenolpyruvate to the (Mg-enzyme) complex.Studies of substrate inhibition by ADP and phosphoenolpyruvate at different concentrations of the free. magnesium ion suggested formation of enzyme complexesof the nature: (Mg-enzyme-MgADP-ADP), (Mg-enzyme-phosphoenolpyruvate-phosphoenolpyruvate), (Mg-enzyme-Mg-phosphoenolpyruvate-phosphoenolpyruvate) and (Mg-enzyme-MgADPphosphoenolpyruvate-phosphoenolpyruvate). The patterns obtained in the product inhibition experiments could be explained by the formation of dead-end complexes containing ADP and ATP as well as ADP and pyruvate.
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Published date: 1977
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Local EPrints ID: 467247
URI: http://eprints.soton.ac.uk/id/eprint/467247
PURE UUID: bc6cf5d0-8b0a-45c1-a1c9-0bb6e76efe1c
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Date deposited: 05 Jul 2022 08:16
Last modified: 05 Jul 2022 08:16
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Author:
Colin John Newton
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