Variation of PFK activity in model membrane systems

Ji, Cheng (2005) Variation of PFK activity in model membrane systems. University of Southampton, Doctoral Thesis.

Record type: Thesis (Doctoral)

Abstract

PFK (phosphofructokinase or fructose-6-phosphate-l kinase) is a key enzyme in the glycolysis pathway. It catalyses the transfer of the terminal phosphate from adenosine triphosphate to fructose 6-phosphate and sets the overall rate of glycolysis. Cellular membrane is one of the most complex yet important structures in cells. Many essential cell events have been found relative to membrane confirmations and other properties such as membrane surface charge and stored curvature energy. Several glycolytic enzymes including PFK have been reported to interact with cell membrane components and their functions are thus regulated by a complicated mechanism. It has been proposed that the membrane-enzyme interaction is essential for cell's biological functions. The aim of the research described in this thesis was to investigate whether PFK activity could be regulated by membrane lipid composition in a way that is consistent with stored elastic energy playing a dominant role in the regulation. Using large unilamellar vesicles as model system of biological membranes, activities of PFK from Bacillus stearothermophilus were tested in five vesicles systems, which were chosen so as to give particular changes in membrane stored elastic energy. The experimental methodology for the enzyme assays were studied and optimized first before the final PFK assays were tested. The experimental results showed a slight enhancement of enzyme activity.

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