Divided by two gives us 9.4. So the pi, the isoelectric point for this amino acid, which is basically Lysine, is equal to 9.8. So at a PH of 9.8, these two charges will exactly cancel out this negative charge that is found on the alpha carboxyl group. And finally, let's move on to case four. So, if we have an ionizable side chain group, but it is neither basic nor acidic, so we're basically dealing with two cases. And these two cases are 15 and tyrosine.