Notes:
The isoelectric point is the pH at which the net charge of a molecule is neutal. For instance, if a molecule has multiple chargable groups, and at a certain pH, these seperate charges add up to zero, this pH would be an isoelectric point.
At a pH higher than the isoelectric point, the net charge is negative. At a pH lower than the isoelectric point, the net charge is negative.
This point can be calculated by averaging pKas nearest the pH where the molecule is neutal.