These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Phosphopeptide enrichment on functionalized polymer microspots for MALDI-MS analysis.
    Author: Wang WH, Bruening ML.
    Journal: Analyst; 2009 Mar; 134(3):512-8. PubMed ID: 19238288.
    Abstract:
    On-plate enrichment of phosphopeptide digests followed by MALDI-MS is attractive for analyzing small quantities of phosphoproteins because it involves minimal sample handling and reduces sample loss. This work describes a method for modification of Si wafers, which serve as MALDI plates, with 250 microm-diameter microspots of phosphopeptide-binding polymer brushes enclosed by a hydrophobic poly(dimethylsiloxane) (PDMS) layer. Formation of the patterned surface occurs by heating a patterned PDMS stamp on a Si wafer, growing the polymer brushes from the Si exposed in the stamp pores, and removing the stamp to leave behind a residual layer of PDMS surrounding the brushes. Pinning and evaporation of a sample droplet on the microspot concentrate samples and enrich phosphopeptides through binding to the small area. After rinsing with acidic solution to remove unwanted peptides, a drop of matrix solution elutes the phosphopeptides and crystallizes only on the microspot. With beta-casein and ovalbumin digests, the use of microspots rather than 2 mm-diameter polymer spots for phosphopeptide enrichment results in a 5-fold decrease in MALDI-MS detection limits and low-femtomole level sensitivity. Improved enrichment of phosphopeptides on the polymer microspots from samples that contain a 10-fold molar excess of peptides from a non-phosphorylated protein digest is also possible with the help of a sonication-assisted rinse. Thus, arrays of microspots are attractive for analyzing femtomole amounts of relatively pure protein, such as that obtained by immunoprecipitation.
    [Abstract] [Full Text] [Related] [New Search]