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How a signal ends?

  1. Apr 1, 2010 #1
    In the presence of the signal molecules, cascades of enzyme activation take place usually by phosphorylation. When signal ceases activated enzymes (phosphorylated or dephosphorylated) are still there, so they can go on doing what they were doing before. My question is how this enzymes are deactivated after the signal ends? I am looking for basic mechanism (schematic).
  2. jcsd
  3. Apr 1, 2010 #2


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    There are enzymes called phosphatases that can remove phosphates from proteins and other phosphorylated molecules. In fact, most post-translational modifications of proteins can be reversed by some enzymes (e.g. deubiquitinases remove ubiquitin, deacetylases remove acetylation, etc.).
  4. Apr 1, 2010 #3
    Are these phosphatase still there even when no signal is present?
    Or they need to be activated or synthesized when a particular signal ends (seems very unlikely)?
  5. Apr 2, 2010 #4
    Phosphatases are always there they don't need to be synthesized. May be when there is too much product from the enzyme reaction it can act as cofactor for Phosphatase enzymes and reverse the reaction. Like negative feedback!!
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