title: Feasibility assessment of a novel selective peptide derivatization strategy for sensitivity enhancement for the liquid chromatography/tandem mass spectrometry bioanalysis of protein therapeutics in serum.
abstract: BACKGROUND
  Sensitivity is one major challenge limiting the application of liquid chromatography/tandem mass spectrometry (LC/MS/MS) methods for bioanalysis of proteins. A novel selective peptide derivatization (SPD) strategy was proposed to improve assay sensitivity. The main concept of the SPD strategy is to selectively derivatize surrogate peptides of the target protein in the digests, while not derivatizing the abundant background peptides, thereby improving the separation of target peptides during sample extraction and chromatography, and increasing the sensitivity. Additional benefits may help improve sensitivity include (1) increased ionization efficiency; (2) improved fragmentation pattern; and (3) increased sample extraction recovery of target peptides.
  
  
  METHODS
  Feasibility assessment of the SPD strategy was conducted using BMS-986012, a monoclonal antibody, as the model protein, and with malondialdehyde (MDA) to selectively derivatize the arginine-containing surrogate peptide SLIY in tryptic-digested monkey serum samples.
  
  
  RESULTS
  The decreased polarity and basicity of the MDA-derivatized peptide SLIY (MDA-SLIY) helped improve its separation from the background peptides during solid-phase extraction (SPE) and chromatography. The recovery of MDA-SLIY was 36.1-44.2%, which was ~3-fold higher than the recovery of peptide SLIY (11.9-16.1%). There was no significant ion suppression for MDA-SLIY. Overall, SPD improved the sensitivity ~5-fold. SPD methodology was then successfully applied to the development of a sensitive LC/MS/MS assay for BMS-986012 in monkey serum.
  
  
  CONCLUSIONS
  This work demonstrates the feasibility of the SPD strategy for sensitivity enhancement. SPD can provide a simple, cost-efficient, and antibody-free sample preparation approach to improve sensitivity.
authors.affiliation: Bioanalytical Sciences, Analytical & Bioanalytical Development, Bristol-Myers Squibb, Princeton, NJ, 08543, USA.
authors.forename: Long
authors.initials: L
authors.lastname: Yuan
authors.forename: Anna
authors.initials: A
authors.lastname: Mai
authors.forename: Anne-Françoise
authors.initials: AF
authors.lastname: Aubry
authors.forename: Mark E
authors.initials: ME
authors.lastname: Arnold
authors.forename: Qin C
authors.initials: QC
authors.lastname: Ji
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000097:blood* / Q000737:chemistry; D002853:Chromatography, Liquid / Q000379:methods*; D005240:Feasibility Studies; D000882:Haplorhini; D006801:Humans; D008315:Malondialdehyde / Q000737:chemistry; D008956:Models, Chemical; D010446:Peptide Fragments / Q000097:blood* / Q000737:chemistry; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D000911:Antibodies, Monoclonal; D010446:Peptide Fragments; D008315:Malondialdehyde