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An oligomeric protein has a molecular weight of 443000. A 610 mg sample was trea

ID: 163705 • Letter: A

Question

An oligomeric protein has a molecular weight of 443000. A 610 mg sample was treated with an excess of 1-fluoro-2.4-dinitrobenzene (Sanger's reagent) until the reaction was complete. Next the peptide bonds were hydrolyzed by heating with concentrated HCI. the product of the complete hydrolysis contained 1.3 mg of the compound shown below, and no other 2.4-dinitrophenyl derivatives of the a-amino groups of other amino acids could be found, how many polypeptide chains are in this protein? (Enter your answer as a whole number).

Explanation / Answer

Molecular weight of given protein is 443000

Complete hydrolysis = 1.3/443000 = 2.934

Treated sample = 610/443000 = 0.001

Remaining polypeptide chains in protein = 2.934/0/001 = 3.408

Therefore, we got 3 polypeptide chains after complete hydrolysis.