Biochemistry 4th Edition by Christopher Mathews,Kensal van Holde, Dean Appling, Spencer Anthony Cahill

Exercise 15

Note that some of these problems refer to information presented in the Tools of Biochemistry 5A-D.
You have discovered a novel protein that has a pI = 5.5. To study the functional properties of this new protein, your research group has made a mutant that contains two amino acid changes: a surface phenylalanine residue in the normal protein has been replaced by histidine (side chain pK a = 6.1), and a surface glutamine has been replaced by glutamic acid (side chain pK a = 6.0). Is the pI of the. mutant protein predicted to be greater than, less than, or the same as the pI of normal protein Support your answer with the appropriate calculation.