Carboxypeptidase G is a lysosomal, thiol-dependent protease, which progressively cleaves γ-glutamyl pteroyl poly-γ-glutamate yielding pteroyl-α-glutamate (folic acid) and free glutamate. It is considered highly specific for the γ-glutamyl bond, but not for the C-terminal amino acid of the leaving group.1 Molecular mass of this homodimer is approximately 90 kDa. The enzyme is activated by Zn2+ ions.