A normal polypeptide and a mutant of the polypeptide were hydrolyzed by an endopeptidase under the same

Question:

A normal polypeptide and a mutant of the polypeptide were hydrolyzed by an endopeptidase under the same conditions. The normal and mutant differ by one amino acid residue. The fingerprints of the peptides obtained from the normal and mutant polypeptides are as shown. What kind of amino acid substitution occurred as a result of the mutation (That is, the substituted amino acid more or less polar than the original amino acid? Is its pI lower or higher?)