Dr. Kim S. Tree was preparing a manuscript for publication in which she reported that the pI

Question:

Dr. Kim S. Tree was preparing a manuscript for publication in which she reported that the pI of the tripeptide Lys-Lys-Lys was 10.6. One of her students pointed out that there must be an error in her calculations because the pKa of the ε-amino group of lysine is 10.8 and the pI of the tripeptide has to be greater than any of its individual pKa values. Was the student correct?