So that means there are three different amino acids that fit this category. So we have Lysine, we have arginine and we have HistoGene. Now in this particular case, what we have to do is we basically take the sum of the PKA value of that side chain group and the PKA value of the alpha amino group. 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.