UNIT 18.8 Measuring Protein-Protein Interactions by Equilibrium Sedimentation

  1. Andrea Balbo1,
  2. Patrick H. Brown1,
  3. Emory H. Braswell2,
  4. Peter Schuck2

Published Online: 1 NOV 2007

DOI: 10.1002/0471142735.im1808s79

Current Protocols in Immunology

Current Protocols in Immunology

How to Cite

Balbo, A., Brown, P. H., Braswell, E. H. and Schuck, P. 2007. Measuring Protein-Protein Interactions by Equilibrium Sedimentation. Current Protocols in Immunology. 79:18.8:18.8.1–18.8.28.

Author Information

  1. 1

    National Institutes of Health, Bethesda, Maryland

  2. 2

    University of Connecticut, Storrs, Connecticut

Publication History

  1. Published Online: 1 NOV 2007
  2. Published Print: NOV 2007


This unit describes basic principles and practice of sedimentation equilibrium analytical ultracentrifugation for the study of reversible protein interactions, such as the characterization of self-association, heterogeneous association, and binding stoichiometry, as well as the determination of association constants. Advanced tools such as mass conservation analysis, multiwavelength analysis, and global analysis are introduced and discussed in the context of the experimental design. A detailed protocol guiding the investigator through the experimental steps and the data analysis is available as an internet resource. Curr. Protoc. Immunol. 79:18.8.1-8.18.28. © 2007 by John Wiley & Sons, Inc.


  • sedimentation equilibrium;
  • sedimentation velocity;
  • chemical equilibria;
  • reversible interactions;
  • multi-protein complex;
  • analytical ultracentrifugation