And the PKA value of this carboxylic acid is 4.1. So what that means is if we're at 4.1, we'll have 50% of the acid and 50% of the conjugate base. If we're below a PH of 4.1, this will predominate. If we're above a PH of 4.1, this will predominate. And what that means is, at the normal physiological PH, because that is higher than 4.1, these ions will predominate over these neutral species. And so, because they're going to have a full negative charge, they can actually form many ionic bonds.