title: Development of an SRM method for absolute quantitation of MYDGF/C19orf10 protein.
abstract: To develop a MS-based selected reaction monitoring (SRM) assay for quantitation of myeloid-derived growth factor (MYDGF) formerly chromosome 19 open reading frame (C19orf10).
  
  
  
  Candidate reporter peptides were identified in digests of recombinant MYDGF. Isotopically labeled forms of these reporter peptides were employed as internal standards for assay development. Two reference peptides were selected SYLYFQTFFK and GAEIEYAMAYSK with respective LOQ of 42 and 380 attomole per injection.
  
  
  
  Application of the assay to human serum and synovial fluid determined that the assay sensitivity was reduced and quantitation was not achievable. However, the partial depletion of albumin and immunoglobulin from synovial fluids provided estimates of 300-650 femtomoles per injection (0.7-1.6 nanomolar (nM) fluid concentrations) in three of the six samples analyzed.
  
  
  
  A validated sensitive assay for the quantitation of MYDGF in biological fluids was developed. However, the endogenous levels of MYDGF in such fluids are at or below the current levels of quantitation. The levels of MYDGF are lower than those previously reported using an ELISA. The current results suggest that additional steps may be required to remove high abundance proteins or to enrich MYDGF for SRM-based quantitation.
authors.affiliation: Department of Internal Medicine, Manitoba Centre for Proteomics and Systems Biology, University of Manitoba and Health Sciences Centre, Winnipeg, MB, Canada.
authors.forename: Ravi C
authors.initials: RC
authors.lastname: Dwivedi
authors.affiliation: Department of Internal Medicine, Manitoba Centre for Proteomics and Systems Biology, University of Manitoba and Health Sciences Centre, Winnipeg, MB, Canada.
authors.forename: Oleg V
authors.initials: OV
authors.lastname: Krokhin
authors.affiliation: Department of Internal Medicine, Manitoba Centre for Proteomics and Systems Biology, University of Manitoba and Health Sciences Centre, Winnipeg, MB, Canada.
authors.forename: Hani S
authors.initials: HS
authors.lastname: El-Gabalawy
authors.affiliation: Department of Internal Medicine, Manitoba Centre for Proteomics and Systems Biology, University of Manitoba and Health Sciences Centre, Winnipeg, MB, Canada.
authors.forename: John A
authors.initials: JA
authors.lastname: Wilkins
mesh_terms: D000418:Albumins / Q000737:chemistry; D000595:Amino Acid Sequence; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000175:diagnosis* / Q000473:pathology; D001681:Biological Assay / Q000379:methods* / Q000592:standards; D002247:Carbon Isotopes; D011232:Chemical Precipitation; D006801:Humans; D007074:Immunoglobulin G / Q000737:chemistry; D007378:Interleukins / Q000097:blood / Q000302:isolation & purification*; D007553:Isotope Labeling / Q000379:methods; D057230:Limit of Detection; D013058:Mass Spectrometry / Q000379:methods* / Q000592:standards; D009587:Nitrogen Isotopes; D010455:Peptides / Q000032:analysis / Q000737:chemistry; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry; D013582:Synovial Fluid / Q000737:chemistry
chemical_list: D000418:Albumins; D002247:Carbon Isotopes; D007074:Immunoglobulin G; D007378:Interleukins; C464565:MYDGF protein, human; D009587:Nitrogen Isotopes; D010455:Peptides; D011994:Recombinant Proteins
keywords: C19orf10; MYDGF; SRM; Serum; Synovial fluid