Enzyme required practical

Discussion in 'Supporting Biology' started by clairelucas, Nov 16, 2017.

  1. Does anyone here also have a problem with this practical? If I set up as per protocol, the starch breaks down so quickly their/my first reading/iodine test already has gone? I am pretesting it before this afternoon, but I may have to serially dilute the enzyme or something.. Seem to remember similar problem last time. What am I doing wrong?
    ps only trialling with pH6 as should be the fastest..
  2. how often are you testing the soln - we do every 15 seconds...if it goes quicker than that you will need to dilute the enzyme down - enzyme activities seem to be extremely variable...hope it works for you
    Beaker likes this.
  3. I've just diluted down the enzyme from 1% to 0.1% and it works perfectly - maybe I just misread it?!
  4. 2 of our teachers have trilled it and mentioned the same problem.
    Done this with 1%amylase.
    Will suggest Claire's idea of diluting the enzyme.
    Beaker likes this.
  5. You are right to trial the enzyme (Is it Diastase?) at it's pH optima. You need to dilute the enzyme to say 0.1% w/v and the starch to 1-2%w/v. I've followed this by continuous colorimetry and had excellent results. In fact the rate was remarkably constant.:)

    Last edited: Jun 5, 2018