Which Amino Acids Are Titratable?

We are thus left with the titratable groups in the side chains of Asp, Glu, Tyr, Cys, His (only the transition from His⁺ to His⁰), Lys and Arg as well as the two terminal groups. For reasons of simplicity we will refer to Asp, Glu, Cys, Tyr and the C-terminus as acids, and to His, Arg, Lys and the N-terminus as bases.

Does glycine have a titratable R group?

Because there are two titratable groups in glycine, we get two points at which the amino acid is half-titrated. ... If we look at the chemistry of glutamic acid, for example, the a-CO₂H group on the R substituent has an acidity that is close to that of acetic acid.

Which amino acids are anionic?

All amino acids can act as monovalent anion; the acidic members glutamic acid and aspartic acid as well as cysteine and tyrosine can form both monovalent and divalent anions.