Combining SAMDI Mass Spectrometry and Peptide Arrays to Profile Phosphatase Activities

Lindsey C. Szymczak, Che Fan Huang, Eric J. Berns, Milan Mrksich*

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingChapter

12 Scopus citations


Phosphatases, the enzymes responsible for dephosphorylating proteins, play critical roles in many cellular processes. While their importance is widely recognized, phosphatase activity and regulation remain poorly understood. Currently, there are few assays available that are capable of directly measuring phosphatase activity and specificity. We have previously introduced SAMDI (self-assembled monolayers on gold for matrix-assisted laser desorption/ionization) mass spectrometry as a technique to profile the substrate specificities of enzymes. SAMDI mass spectrometry assays are well suited to examine phosphatase activities and offer many advantages over current methods. This technique uses monolayers that terminate with a peptide or molecular enzyme substrate and allows for enzyme reactions to be performed on a surface that can easily be rinsed and analyzed by mass spectrometry without the need for analyte labeling. In this chapter, we describe the process of combining SAMDI mass spectrometry with peptide arrays to study the substrate specificities of two protein tyrosine phosphatases.

Original languageEnglish (US)
Title of host publicationMethods in Enzymology
EditorsKaren N. Allen
PublisherAcademic Press Inc
Number of pages15
ISBN (Print)9780128138816
StatePublished - Jan 1 2018

Publication series

NameMethods in Enzymology
ISSN (Print)0076-6879
ISSN (Electronic)1557-7988


  • High-throughput experiment
  • Label-free
  • Peptide array
  • Protein tyrosine phosphatase

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology


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