For basic amino acids with pH > 7, peptides will exist as cations. For example, when the substituents are basic, that is, R1 = CH2CONH2 and R2 = (CH2)4NH2 or when R1 = (CH2)4NH2 and R2 = (CH2)4NH2 or when R1 = CH2OH and R2 = (CH2)4NH2 or when R1 = (CH2)4NH2 and R2 = CH3.