title: Remarkable temporal stability of high-abundance human plasma proteins assessed by targeted mass spectrometry.
abstract: OBJECTIVE
  To examine temporal fluctuations in selected plasma protein levels over a period of nearly 4 months and assess biological variation of these proteins across a healthy population cohort.
  
  
  METHODS
  Plasma was collected from ten healthy volunteers over two time-courses: (i) weekly for 4 weeks; (ii) bimonthly over 4 months and depleted of albumin and IgG. SRM MS was used to determine the relative quantitation of 31 plasma proteins commonly observed in biomarker studies over these time courses. Estimates of between-subject and within-subject biological variances determined by SRM were calculated for each protein.
  
  
  RESULTS
  Replicate analysis demonstrated the high precision of SRM assays of plasma proteins. Statistical analysis indicated that none of the measured proteins exhibited significant temporal fluctuations over either time course. Overall, time-based intraindividual quantitative variation of plasma protein levels was considerably lower than biological variation occurring between individual volunteers.
  
  
  CONCLUSIONS
  This study is the first to show robust temporal stability of the plasma proteome in healthy individuals using SRM-based peptide quantitation. This is important as it provides a strong basis for reliable detection of disease/treatment-related changes of these plasma proteins and others using SRM.
authors.affiliation: Department of Chemistry & Biomolecular Sciences, Macquarie University, Sydney, Australia.
authors.forename: Sarah A
authors.initials: SA
authors.lastname: Randall
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: McKay
authors.forename: Dana
authors.initials: D
authors.lastname: Pascovici
authors.forename: Kate
authors.initials: K
authors.lastname: Mahon
authors.forename: Lisa
authors.initials: L
authors.lastname: Horvath
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Clarke
authors.forename: Mark P
authors.initials: MP
authors.lastname: Molloy
mesh_terms: D000595:Amino Acid Sequence; D001798:Blood Proteins / Q000737:chemistry / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D013058:Mass Spectrometry / Q000379:methods*; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry; D055550:Protein Stability; D013997:Time Factors
chemical_list: D001798:Blood Proteins; D010455:Peptides