UNIT 11.7 Protein Tyrosine Phosphatase Assays

  1. Ulrike Lorenz

Published Online: 1 APR 2011

DOI: 10.1002/0471142735.im1107s93

Current Protocols in Immunology

Current Protocols in Immunology

How to Cite

Lorenz, U. 2011. Protein Tyrosine Phosphatase Assays. Current Protocols in Immunology. 93:11.7:11.7.1–11.7.12.

Author Information

  1. The Beirne Carter Center for Immunology Research and Department of Microbiology, University of Virginia, Charlottesville, Virginia

Publication History

  1. Published Online: 1 APR 2011
  2. Published Print: APR 2011


Tyrosine phosphorylation and dephosphorylation of proteins play a critical role in many processes of the immune system, from early development to fully differentiated effector function. Since the opposing actions of protein tyrosine kinases (PTKs) and protein tyrosine phosphatases (PTPs) determine the steady-state level of tyrosine phosphorylation on a given protein, it is often important for mechanistic studies to determine the specific activities of PTKs and PTPs. PTPs are defined by their enzymatic activity that catalyzes the dephosphorylation of phosphotyrosine residues. This unit focuses on methods to determine the enzymatic activity of PTPs. While there are many varieties of PTP assays, the focus in this unit is on immune complex PTP assays, which do not require elaborate biochemical purifications and are commonly used to test the activities of specific PTPs in the immune system. Curr. Protoc. Immunol. 93:11.7.1-11.7.12. © 2011 by John Wiley & Sons, Inc.


  • protein tyrosine phosphatase;
  • protein tyrosine phosphatase assay;
  • immunoprecipitation;
  • pNPP;
  • phosphoprotein;
  • phosphopeptide;
  • malachite green assay;
  • radioactively labeled;
  • phosphoproteins