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Why catalysts affect forward and reverse reactions?

  1. Nov 18, 2014 #1
    Based on the very basic understanding on enzymes I have gained from Year 12 Biology and Chemistry, I don't undesrtand why the enzymes specific shape also helps the reverse reaction. I guess my trouble would be due to the simplified diagrams I've seen from Biology, where only the forward reaction is shown to be catalysed.

    So if anyone has any explanations or links, that would be great.

    Also, a side question, does anyone have a link that compares organic and artificial catalysts; I've heard that enzymes are ridiculously more effective than standard artificial catalysts, but I can't really find what I'm looking for on the interenet. What do you compare? Is it the Turn Over Number?

    Anyway, any clarification would be greatly appreciated.
     
  2. jcsd
  3. Nov 19, 2014 #2
    I can't comment on the first part, but one quantity used to measure the 'efficiency' of a catalyst is the number of moles of the product per unit mass (often mmol/g).
     
  4. Nov 19, 2014 #3

    Borek

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    Staff: Mentor

    In general you have:

    reactant + enzyme <-> intermediate complex <-> product + enzyme

    So in principle the reaction can go both ways. Typically one direction is preferred due to the thermodynamics of the process.
     
  5. Nov 20, 2014 #4
    Thanks Vagn and Borek for your prompt replies.

    I guess I am just incorrectly visualising the "shape" of the active site, and how it bonds with the substrate, whether that be the reactants or products of a particular reaction. It seems strange that an enzyme could not be manufactured to have a "shape" that only works for the forward reaction. Can you think of what exactly I might be missing?
     
  6. Nov 20, 2014 #5

    Borek

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    Staff: Mentor

    Enzyme has to fit both the initial and the final "shape", change is continuous.
     
  7. Nov 22, 2014 #6
    Ok, that makes sense. Thanks for your help.
     
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