1. when adding base, carboxyl, then amino group, loses proton.
2. two moles of bases added to deprotonate one most of mass amino acids
3. buffer capacity of AA greatest at or near pH of two disso. pKa1 and pKa2; at isoelectric point, its buffering capacity is minimal
4. some AA has acidic or basic side chains; to find pI of these amino acids, avg the two acidic pKa's if side chain is acidic and pKa's if side chain is basic
5. possible to perform reverse