IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Biomaterials Thursday Sessions
       Session BI-ThP

Paper BI-ThP3
Studies of Phosphopeptides on Metal Impregnated Plasma Polymer Surfaces

Thursday, November 1, 2001, 5:30 pm, Room 134/135

Session: Biomolecule and Cell Poster Session
Presenter: J. Zhang, The University of Texas at Arlington
Authors: J. Zhang, The University of Texas at Arlington
J.D. Whittle, The University of Texas at Arlington
H. Qiu, The University of Texas at Arlington
R.B. Timmons, The University of Texas at Arlington
G.R. Kinsel, The University of Texas at Arlington
Correspondent: Click to Email
Surface-protein interactions play an important role in the fields of biology and medicine. Recent work in our group has focused on the binding affinity of phosphopeptides for metal ions immobilized on vinyl acetic acid modified PET substrates. Our work demonstrates that, under specific solution conditions, phosphopeptides have high binding affinities for copper. This observation has been utilized to purify / clean-up phosphopeptides on-probe before sample analysis by Matrix Assisted Laser Desorption / Ionization (MALDI) Mass Spectrometry (MS). Our initial studies focus on the development of surfaces for extraction / isolation of phosphopeptides via coordination with surface bound metal ions. PET substrates (4.8 mm diameter disks) were modified by pulsed RF plasma deposition of polymerized vinyl acetic acid. Metal ions were incorporated into the vinyl acetic acid modified PET substrates by immersion of the substrates into various metal ion solutions. Specific binding of phosphopeptides to the surface was first demonstrated by exposure of the metal impregnated film to a mixture of the peptide buccalin and the phosphopeptide p60 substrate II. Washing of the surface with the buffer MES (pH = 5.5)/10%acetonitrile led to selective removal of the buccalin peptide from the surface film. (This step was confirmed by MALDI analysis of the wash solution.) Similar methods have also been successfully applied to the extraction of phosphopeptides from alpha-casein tryptic digests. The purification of phophopeptides resulted in an increase in the peptide MALDI ion signal and improved ion signal resolution. Additional studies have focused on the effect of changes in the metal ion used for phosphopeptide binding, changes in the solutions used for washing / peptide release, and metal-ion binding of histidine-rich peptides.