52 research outputs found
Robustness in Glyoxylate Bypass Regulation
The glyoxylate bypass allows Escherichia coli to grow on carbon sources with only two carbons by bypassing the loss of carbons as CO2 in the tricarboxylic acid cycle. The flux toward this bypass is regulated by the phosphorylation of the enzyme isocitrate dehydrogenase (IDH) by a bifunctional kinase–phosphatase called IDHKP. In this system, IDH activity has been found to be remarkably robust with respect to wide variations in the total IDH protein concentration. Here, we examine possible mechanisms to explain this robustness. Explanations in which IDHKP works simultaneously as a first-order kinase and as a zero-order phosphatase with a single IDH binding site are found to be inconsistent with robustness. Instead, we suggest a robust mechanism where both substrates bind the bifunctional enzyme to form a ternary complex
Phosphorylation of isocitrate dehydrogenase as a demonstration of enhanced sensitivity in covalent regulation
In vivo phosphorylation of isocitrate lyase inEscherichia coli andAcinetobacter calcoaceticus
The regulatory properties of isocitrate dehydrogenase kinase and isocitrate dehydrogenase phosphatase from Escherichia coli ML308 and the roles of these activities in the control of isocitrate dehydrogenase
Evidence of Protein Kinase Activity and Characterization of Substrate Proteins in Escherichia Coli
Regulation of isocitrate dehydrogenase by phosphorylation in Escherichia coli K-12 and a simple method for determining the amount of inactive phosphoenzyme
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