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Table 3 Results of iodination of cetuximab with addition of HEPES and/or lactose and iodination of BoNT-A

From: The ultimate radiochemical nightmare: upon radio-iodination of Botulinum neurotoxin A, the introduced iodine atom itself seems to be fatal for the bioactivity of this macromolecule

Product (50 μg) HEPES (μmol) Lactose (mg) IODOGEN (μg) 125 I (MBq) Labelling efficiency (%) 125 I/product molar ratio
Cetuximab 0 0 2.5 19.6 80.7 0.59
Cetuximab 0 0.625 2.5 19.3 78.3 0.56
Cetuximab 1 0 2.5 15.7 43.5 0.25
Cetuximab 1 0.625 2.5 30.2 43.5 0.49
Cetuximab 1 0.625 1.25 + 1.25 15.6 50.2 0.29
Cetuximab 1 0.625 1.25 + 1.25 93.4 51.8 1.80
Cetuximab 1 0.625 1.25 + 1.25 146.2 43.0 2.34
BoNT-A -a -a 1.25 + 1.25 97.2 51.5 1.86
BoNT-A -a -a 1.25 + 1.25 98.3 51.8 1.90
  1. Conditions: 2.5 μg IODOGEN in 35 μL IODOGEN/acetonitrile added at t = 0 or 1.25 μg IODOGEN in 17.5 μL IODOGEN/acetonitrile added at t = 0 and at t = 45. Other conditions: 250 μL reaction volume and 90-s reaction time. Radiochemical purity was >98.5% in all experiments.
  2. aReconstituted BoNT-A contained HEPES (20 mM) and lactose (1.25%); this was not purposely added.