Abstract
The sensitivity to regulation of proteins undergoing covalent modification can be greatly increased when the substrates saturate the converter enzymes. This phenomenon, termed zero-order ultrasensitivity, has been found to occur in the reversible phosphorylation of isocitrate dehydrogenase. The possibility that this enhanced sensitivity is a common feature of covalent regulatory systems is discussed.
Publication types
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Research Support, U.S. Gov't, Non-P.H.S.
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Allosteric Regulation
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Enzyme Activation
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Isocitrate Dehydrogenase / metabolism*
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Kinetics
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Phosphoprotein Phosphatases / metabolism
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Phosphoproteins / metabolism
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Phosphorylation
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Protein Kinases / metabolism
Substances
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Phosphoproteins
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Isocitrate Dehydrogenase
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Protein Kinases
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Phosphoprotein Phosphatases