Transcript The Behavior of Proteins: Enzymes, Mechanisms

The Behavior of Proteins:
Enzymes, Mechanisms and
Control
Chapter 7
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
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What are allosteric enzymes?
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Allosteric: Greek allo + steric - other + shape
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Allosteric enzyme: an oligomer whose biological
activity is affected by other substances binding to it
 these substances change the enzyme’s activity by
altering the conformations of its 4°structure
How are allosteric enzymes controlled?
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Allosteric effector: a
substance that modifies the
behavior of an allosteric
enzyme

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allosteric inhibitor
allosteric activator
How are allosteric enzymes controlled?
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End product of the sequence
of reactions inhibits first
reaction in the series
Allosteric Enzymes
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The key to allosteric behavior is the existence of multiple
forms for the 4°structure of the enzyme

allosteric effector: a substance that modifies the 4°
structure of an allosteric enzyme

homotropic effects: allosteric interactions that occur when
several identical molecules are bound to the protein

heterotropic effects: allosteric interactions that occur
when different substances are bound to the protein
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