Now, all of these Lysine amino acids at the normal physiological PH of around seven have a full positive charge on that nitrogen. And that's because to actually deprotonate our nitrogen, we really have to increase our PH. We have to make it basic, because the PKA value of this nitrogen is ten. Remember, what the PKA means is if the PH is equal to the PKA, then that is the point at which half of these molecules are deprotonated and half of them are protonated. So if we're below the PKA of ten at the physiological PH of seven, that means all of these Lysine amino acids will be protein. It will have a full positive charge on the nitrogen.