pKa of NH3+ of Gly is 9.78 and pKa of COOH of Glu is 4.07. Therefore, pI=(9.78+4.07)/2=6.925, at this pH, all COOH groups are in COO- state and all NH2 groups are in NH3+ state, the net charge is then zero. Did I do this correct?
Is the common pattern to take the lowest pKa of NH3+ and the highest pKa of COOH group that is the part of an amino acid and to average these values? That way the net charge will always be zero. True?