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Homework Help: Estimating number of amino acids with protein molecular mass

  1. Mar 22, 2017 #1
    1. The problem statement, all variables and given/known data
    Suppose you were told you had a protein with molecular mass of 65,000 g/mol. Show how you would estimate the number of amino acids present in this protein. Keep in mind that you cannot calculate the exact number, the point of this is to approximate how many amino acids are present.

    2. Relevant equations
    I think I would need to divide the protein's weight by the average weigh of its amino acids, right? Problem is how am I suppose to do this when no average weight for amino acids is given in the problem?

    3. The attempt at a solution
    I just divided 65000 Da by 110 Da (googled average weight of an amino acid) and got about 590 amino acids in the protein. I am completely unsure if this is correct as my lab never discussed this at all while doing bio-spectroscopy. Help would be appreciated.
    Last edited: Mar 22, 2017
  2. jcsd
  3. Mar 22, 2017 #2


    User Avatar
    Science Advisor
    2017 Award

    Yes, that is the correct approach. Your instructor likely expected you to look up the average MW of an amino acid as it is fairly easily found either in a textbook or through Google.
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