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Homework Help: Experimental Molecular Weight higher than Literature Value

  1. Apr 15, 2008 #1
    1. The problem statement, all variables and given/known data
    I just purified alkaline phosphatase, and my calculated molecular weight is 100000 g/mol, while literature value is 89000 g/mol. According to how others in my lab did calculations, my calculations are performed correctly, so I am left to explain why my purification is higher than expected.

    2. Relevant equations

    3. The attempt at a solution
    I was thinking that since alkaline phosphatase can be inhibited by EDTA, my "purified" enzyme contains some EDTA, making the molecular weight higher.
  2. jcsd
  3. Apr 16, 2008 #2


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    Did you purify it by gel electrophoresis? What was the supporting electrolyte? Did you completely dialyze your product?
  4. Apr 18, 2008 #3


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    You do not give any indication of what method used for getting the MW so what can anyone say?
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