“…HYNIC-peptide conjugates are formed via amide linkage formed through reaction of the active ester derivative of the ligand (Figure ). This approach has been used for radiolabeling antibodies, human serum albumin, a variety of medium to high molecular weight proteins, oligopeptides, and small biomolecules. − The issue of the poorly characterized coordination chemistry of the associated bioconjugates, as mentioned previously, detracts from the attractiveness of this ligand system …”