Changes in catalytic activity and association state of pyruvate carboxylase which are dependent on enzyme concentration

Attwood, Paul V. and Geeves, Michael A. (2002) Changes in catalytic activity and association state of pyruvate carboxylase which are dependent on enzyme concentration. Archives of Biochemistry and Biophysics, 401 (1). pp. 63-72. ISSN 0003-9861. (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided)

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The specific activity of chicken liver pyruvate carboxylase has been shown to decrease with decreasing enzyme concentration, even at 100 microM, which is close to the estimated physiological concentration. The kinetics of the loss of enzyme specific activity following dilution were biphasic. Incubation of dilution-inactivated enzyme with ATP, acetyl CoA, Mg2+ + ATP or, to a lesser degree, with Mg2+ alone resulted in a high degree of reactivation, while no reactivation occurred in the presence of pyruvate. The association state of the enzyme before, during, and after dilution inactivation has been assessed by gel filtration chromatography. These studies indicate that on dilution, there is dissociation of the catalytically active tetrameric enzyme species into inactive dimers. Reactivation of the enzyme resulted in reassociation of enzymic dimers into tetramers. The enzyme was shown to form high molecular weight aggregates at high enzyme concentrations.

Item Type: Article
Additional information: 0003-9861 (Print) In Vitro Journal Article
Uncontrolled keywords: Acetyl Coenzyme A/pharmacology Adenosine Triphosphate/pharmacology Animals Chickens Enzyme Reactivators/pharmacology Kinetics Magnesium/pharmacology Osmolar Concentration Protein Structure, Quaternary Pyruvate Carboxylase/antagonists & inhibitors/*chemistry/*metabolism
Subjects: Q Science
Divisions: Faculties > Science Technology and Medical Studies > School of Biosciences > Protein Science Group
Depositing User: Michael Geeves
Date Deposited: 01 Sep 2008 15:36
Last Modified: 22 Apr 2014 13:27
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