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Help requested on simple enzyme experiment

  1. Sep 29, 2005 #1
    Hello every 1
    i'd like assistance regarding a simple enzyme experiment to see how Ph effects enzyme activity, does any 1 have a meathod which can help me carry out such an experiment. I'm going to use H202 as my substrate concentration. This experiment is going to be carried out in a simple lab so theres no need for complex apperatus. A few testubes will work fine.
    The variables i'm keeping constant is
    temperature & substrate concentration
    your help would be appreciated
    thank you
  2. jcsd
  3. Sep 29, 2005 #2


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    What will you use as your source of enzyme? How do you plan to measure the reaction rate? I can tell from your description what your variable is, but can you state it so I'm sure you have the concepts right in your own mind? Also, state your hypothesis.

    These are the questions you need to answer to start setting up the experiment.

    I think it can be done, but it will be best if you work out planning it yourself, and we'll help jog your brain when you get stuck on part of the planning, or to help troubleshoot if it doesn't work the way you plan it.
  4. Sep 29, 2005 #3
    (Ph should be pH .... the negative log of H ions)

    Please include controls wherein no enzyme is added. Concevably the pH itself (which is one of your variables) could affect substrate concentration.
  5. Sep 30, 2005 #4
    well i'm investigating how ph affects Enzyme activity, The enzyme i'll b using is catalase, i'll be varying Ph all other factors such as temperature, substrate concentration, enzyme concentration will be kept the same through out the experiment.
    From what iv read catalase acts on a substate known as H202 better known as hydrogen peroxide and breaks it down into h20+O2 i'll have to think of a way to meassure the ammount of H20 +02 realeased could u please think of a technique that would help me?
  6. Sep 30, 2005 #5


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    Since oxygen is a gas, you would have to capture it to measure it (not let it just escape out the top of your tube). You might have to tinker a bit to find out what works best for the volume you're producing, but you could measure the volume released (I'm assuming this is for a school project, so you don't need to make this extremely accurate).

    Now you still need to state your hypothesis. How do you expect pH to affect the reaction for the enzyme/substrate you're using?
  7. Sep 30, 2005 #6


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    If the oxygen is being created along with water in some sort of enzyme buffer solution, could you simply measure an increase (or decrease) in dissolved oxygen? DO meters were relatively common in the labs I worked through in highschool and college, perhaps they would be sensitive enough?

    OK, a quick search revealed that http://wwwsoc.nii.ac.jp/jsac/analsci/pdfs/a20_0471.pdf [Broken]2. If that first link doesn't work for you, let me know and I can give you a summary.
    Last edited by a moderator: May 2, 2017
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