Zirconium phosphonate-modified porous silicon for highly specific capture of phosphopeptides and MALDI-TOF MS analysis

J Proteome Res. 2006 Sep;5(9):2431-7. doi: 10.1021/pr060162f.

Abstract

Phosphorylation is one of the most important post-translational modifications of proteins, which modulates a wide range of biological functions and activity of proteins. The analysis of phosphopeptides is still one of the most challenging tasks in proteomics research by mass spectrometry. In this study, a novel phosphopeptide enrichment approach based on the strong interaction of zirconium phosphonate (ZrP) modified surface with phosphopeptides has been developed. ZrP modified porous silicon (ZrP-pSi) wafer was prepared to specifically capture the phosphopeptides from complex peptide mixtures, and then the captured phosphopeptides were analyzed by MALDI-TOF MS by directly placing the wafer on a MALDI target. The phosphopeptide enrichment and MALDI analysis were both performed on the ZrP-pSi wafer which significantly reduced the sample loss and simplified the analytical procedures. The prepared ZrP-pSi wafer has been successfully applied for the enrichment of phosphopeptides from the tryptic digest of standard phosphoproteins beta-casein and alpha-casein. The excellent selectivity of this approach was demonstrated by analyzing phosphopeptides in the digest mixture of beta-casein and bovine serum albumin with molar ratio of 1:100. High detection sensitivity has been achieved for the analysis of the phosphopeptides from tryptic digestion of 2 fmol beta-casein on the ZrP-pSi surface.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Molecular Sequence Data
  • Organophosphonates / chemistry
  • Phosphopeptides / analysis*
  • Phosphopeptides / genetics
  • Phosphopeptides / isolation & purification*
  • Proteomics / methods*
  • Silicon / chemistry*
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / instrumentation*
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / methods
  • Zirconium / chemistry

Substances

  • Organophosphonates
  • Phosphopeptides
  • Zirconium
  • Silicon