Calculate the approximate relative molecular mass,Mr,for a protein with 527 amino acid residues.
A)5.27 × 106
B)5.8 × 104
C)4.8
D)1.7 × 10-5
E)Cannot determine without knowing the exact sequence of amino acids.

Question

Quizplus · Accepted Answer

To calculate the relative molecular mass of a protein, we can use the formula:
Mr = (number of amino acid residues x average molecular mass of an amino acid) + molecular mass of water lost in the formation of peptide bonds
The average molecular mass of an amino acid is approximately 110 Da. Water is lost in the formation of each peptide bond between amino acids, so we need to subtract the mass of (n-1) water molecules from the total molecular mass, where n is the number of amino acid residues. Therefore, we can calculate Mr as:
Mr = (527 x 110) - (526 x 18) = 58,090 Da
which is equivalent to 5.8 x 104.

Calculate the Approximate Relative Molecular Mass,Mr,for a Protein with 527