We divide that by two, we get the average, and that is our isoelectric point. So let's take a look at lysine. So Lysine contains this side chain group, and the PK value of Lysine is around 10.8. Now, the PK value of this alpha terminal group, alpha amino terminal group is eight. So notice once again, in this case we have two negative charges on two different groups. In this case, we have two positive charges on two different groups.