An oligomeric protein has a molecular weight of 4.30 x 105. A 870 mg sample was
ID: 259639 • Letter: A
Question
An oligomeric protein has a molecular weight of 4.30 x 105. A 870 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 3.2 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. NO2 How many polypeptide chains are in this protein? (Enter your answer as a whole number) NH-C-COOH CH2 CH2 O2N Number CH3Explanation / Answer
Total weight of the protein sample taken = 870 mg
After FDNB treatment and hydrolysis, weight of the derivative = 3.2 mg
So, Total number of proteins or Polypeptides = 870/3.2
= 272