But when the PH value reaches the PKA value of the side chain group, namely 8.3, what that means is this will begin to lose our h atom. And at the PH value of 8.3, exactly half of the cysteine amino acids will exist in this form, and the other half will exist in this form with a negative charge on that sulfur. Now, if we go above 8.3, then this group will predominate. If we go below 8.3, this group will predominate. Now, for the case of Lysine, the end of the side chain group that is ionizable is this group shown here. So the same exact thing is true for this particular group.