Aspartate isomerization in the complementarity-determining regions of two closely related monoclonal antibodies

The presence of glycine residues on the C-terminal ends proves that the aspartic acid residues (Asp) present in the complementarity-determining regions (CDRs) of the light chains of two recombinant monoclonal antibodies (MAbs) are highly prone to isomerization. Various studies show that the differences in the Asp isomerization rates between the two MAbs are a result of the structural factors like the conformational flexibility, as well as the extent of solvent exposure of the Asp residue.