APPENDIX 3H Analyzing Radioligand Binding Data

  1. Harvey Motulsky1,
  2. Richard Neubig2

Published Online: 1 MAY 2001

DOI: 10.1002/0471140864.psa03hs21

Current Protocols in Protein Science

Current Protocols in Protein Science

How to Cite

Motulsky, H. and Neubig, R. 2001. Analyzing Radioligand Binding Data. Current Protocols in Protein Science. 21:3H:A.3H.1–A.3H.55.

Author Information

  1. 1

    GraphPad Software, San Diego, California

  2. 2

    University of Michigan, Ann Arbor, Michigan

Publication History

  1. Published Online: 1 MAY 2001
  2. Published Print: SEP 2000


A radioligand is a radioactively labeled drug that can associate with a receptor, transporter, enzyme, or any protein of interest. Measuring the rate and extent of binding provides information on the number of binding sites, and their affinity and accessibility for various drugs. Radioligand binding experiments are easy to perform, and provide useful data in many fields. For example, radioligand binding studies are used to study receptor regulation, investigate receptor localization in different organs or regions using autoradiography, categorize receptor subtypes, and probe mechanisms of receptor signaling. This unit reviews the theory of receptor binding and explains how to analyze experimental data. Since binding data are usually best analyzed using nonlinear regression, this unit also explains the principles of curve fitting with nonlinear regression.