Complementary LC-MS/MS Proteomic Analysis of Uremic Plasma Proteins.

Objective: To complement an earlier analysis of protein alterations in plasma from uremic versus healthy subjects by addition of further LC-MS/MS analysis to the previously used MALDI-TOF mass analyses. Methodology: Sequence identifications of tryptic peptides from SDS gel electrophoretic fractions of immunodepleted and HPLC-fractionated plasma was performed from seven chronic kidney disease stage 5 patients (age 55 ± 14 years, glomerular filtration rate 6.9 ± 2.9 mL/minute/1.73 m 2 ) and from seven matched controls. Results: About twice as many proteins were increased in uremic plasma as the previously identified. The identifications included proteins that consistently complement the two identification patterns regarding separate subunits from the same protein complex. Conclusion: Mass spectrometric analysis is applicable to complex plasma proteomes in clinical settings. The LC-MS/MS technique, based on individual peptide sequence analyses, gives increased identifications and also demonstrates feasibility of this technique in clinical practice.