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allosteric effectors

Discussion in 'MCAT Study Question Q&A' started by m25, Sep 20, 2014.

  1. m25


    May 28, 2014
    When allosteric effectors bind to allosteric sites on enzyme, are they binding covalently or noncovalently, or can it bind either way?
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  3. StIGMA

    StIGMA Doctor Professor PhD 7+ Year Member

    Jul 6, 2008
    It is a noncovalent (and therefore reversible). Remember there are no absolutes in biology as you seem to want to believe- so generally think of it as noncovalent.

    In cell biology, "binding" of one molecule to another is nearly always non-covalent. An exception is enzymatic reactions where transient intermediates form.

    However, certain protein modifications, which can occur on allosteric sites, are covalent modifications (such as phosphorylation); this would not be referred to as "binding" of phosphate to the protein- it would be called a covalent modification or post-translational modification. Protein modifications (ie: post-translational modifications) are not, strictly speaking, considered allosteric effectors (which refers to diffusible molecules that non-covalently associate with a site on the protein that is NOT the active site to modify the enzymatic activity of that protein).

    Simple, huh?
    Last edited: Sep 20, 2014

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