APPENDIX 3A Preparation of an Iodinated Radioligand

  1. C. Diane True

Published Online: 1 MAY 2001

DOI: 10.1002/0471142301.nsa03as1

Current Protocols in Neuroscience

Current Protocols in Neuroscience

How to Cite

True, C. D. 2001. Preparation of an Iodinated Radioligand. Current Protocols in Neuroscience. 1:3A:A.3A.1–A.3A.6.

Author Information

  1. NEN Life Science Products, North Billerica, Massachusetts

Publication History

  1. Published Online: 1 MAY 2001
  2. Published Print: NOV 1997


Radioactive tracers are useful for receptor measurement and for radioimmunoassays because of the ease with which radioactive ligands are detected. Typical receptor measurement methods include whole tissue receptor assays, autoradiography, and cell and membrane binding assays. The isotopes most commonly used in receptor measurement studies are tritium, carbon-14, and iodine-125, with the choice of isotope most often based on the specific activity required and the sensitivity and type of detection system available. Its high specific activity and easy detection make I-125 ideal for labeling large peptides and proteins. While the short half-life (60 days) of iodine requires frequent replacement with freshly iodinated compounds, this is also an advantage, as unused portions of radioligand can be held for decay and disposed of as nonradioactive waste. This unit describes the iodination of proteins or peptides using the 125I-labeled Bolton Hunter reagent, a convenient, easy-to-use, nonoxidizing labeling reagent.