title: Removal of sodium dodecyl sulfate from protein and peptide samples with cross-linked [Os(dmebpy)2 Cl](+/2+) -derivatized acrylamide and vinylimidazole copolymer.
abstract: BACKGROUND
  Sodium dodecyl sulfate (SDS) is widely used for the solubilization and denaturation of proteins, but it interferes with liquid chromatography/mass spectrometry (LC/MS), suppressing protein signals or forming adduct ions. A quick and effective clean-up technique of SDS is essential for MS analysis of proteins. Ion-exchange spin columns are commonly used for SDS removal in protein samples.
  
  
  METHODS
  A bulk sample of insoluble, cross-linked [Os(dimethylbipyridine)2 Cl](+/2+) -derivatized poly(acrylamide)-poly(vinylimidazole) copolymer was synthesized and broken into small particles. The polymer was activated by washing with 1:1 ACN/water 50 mM triethylammonium phosphate 0.05% TFA, 0.1% TFA ACN and then 0.1% TFA water. Under acidic aqueous conditions, SDS adsorbs on the activated surfaces of the Os-complexed copolymer particles, but not the proteins and peptides in the same mixtures. Thus, the copolymer can be used to remove SDS from protein and peptide samples. The copolymer-adsorbed SDS is removed by washing with 0.1% TFA ACN, permitting re-use of the copolymer.
  
  
  RESULTS
  Standard myoglobin and some practical protein samples from a biochemistry lab spiked with different concentrations of SDS were successfully cleaned up using this Os-copolymer for LC/MS analyses. Up to 0.2% (w/v %) of SDS can be successfully removed from those protein samples.
  
  
  CONCLUSIONS
  This Os-complexed copolymer provides a new alternative for quick cleanup of SDS from protein samples, and can serve as a new class of metal complex based anion exchanger for protein purification.
authors: Beckman Institute, California Institute of Technology, Pasadena, CA, 91125, USA.
authors: Jie
authors: J
authors: Zhou
authors: Beckman Institute, California Institute of Technology, Pasadena, CA, 91125, USA.
authors: Felicia
authors: F
authors: Rusnak
mesh_terms: D015082:2,2'-Dipyridyl / Q000737:chemistry*; D020106:Acrylamide / Q000737:chemistry*; D002853:Chromatography, Liquid / Q000379:methods; D007093:Imidazoles / Q000737:chemistry*; D013058:Mass Spectrometry / Q000379:methods; D009942:Organometallic Compounds / Q000737:chemistry; D009992:Osmium / Q000737:chemistry*; D010455:Peptides / Q000032:analysis / Q000737:chemistry; D011506:Proteins / Q000032:analysis* / Q000737:chemistry; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry / Q000302:isolation & purification*
chemical_list: D007093:Imidazoles; D009942:Organometallic Compounds; D010455:Peptides; D011506:Proteins; D020106:Acrylamide; D009992:Osmium; D012967:Sodium Dodecyl Sulfate; D015082:2,2'-Dipyridyl