Peptide mapping of proteins in human body fluids using electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry

Abstract

Human body fluids have been rediscovered in the post-genomic era as great sources of biological markers and perhaps particularly as sources of potential protein biomarkers of disease. Analytical tools that allow rapid screening, low sample consumption, and accurate protein identification are of great importance in studies of complex biological samples and clinical diagnosis. Mass spectrometry is today one of the most important analytical tools with applications in a wide variety of fields. One of the fastest growing applications is in proteomics, or the study of protein expression in an organism. Mass spectrometry has been used to find post-translational modifications and to identify key functions of proteins in the human body. In this study, we review the use of human body fluids as sources for clinical markers and present new data that show the ability of Fourier transform ion cyclotron resonance (FTICR) mass spectrometry (MS) to identify and characterize proteins in four human body fluids: plasma, cerebrospinal fluid (CSF), saliva, and urine. The body fluids were tryptically digested without any prior separation, purification, or selection, and the digest was introduced into a 9.4 T FTICR mass spectrometer by direct-infusion electrospray ionization (ESI). Even though these samples represent complex biological mixtures, the described method provides information that is comparable with traditional 2D-PAGE data. The sample consumption is extremely low, a few microliters, and the analysis time is only a few minutes. It is, however, evident that the separation of proteins and/or peptides must be included in the methodology, in order to detect low-abundance proteins and other proteins of biological relevance.

Identification of genetic variants influencing the human plasma proteome

“…Aliquots of 5 μL of plasma from 1,060 individuals, diluted to 20 μL in 50 mM ammonium bicarbonate (NH4HCO3) were centrifuged 16,000 × g for 10 min in 5°C. From the supernatant, 16 μL was digested following the previously published protocol (28). Briefly the plasma samples were transferred into a 96-well plate.…”

Analysis of oversulfation in a chondroitin sulfate oligosaccharide fraction from bovine aorta by nanoelectrospray ionization quadrupole time-of-flight and fourier-transform ion cyclotron resonance mass spectrometry

“…Several studies have demonstrated the potential of FT-ICR MS for complex mixture elucidation, e.g., crude oil samples [28], peptide mixtures from digestion procedures [29], or glycoconjugate mixtures [30]. McClellan et al have studied the fragmentation of regularly sulfated CS-oligosaccharides by use of SORI-CID FT-ICR MS [16] and Aguilan et al demonstrated the potential of Nano-ESI FT-ICR MS for the analysis of ␣-carrageenan sulfated oligosaccharides [31].…”

Peptide and protein characterization by high‐rate electron capture dissociation Fourier transform ion cyclotron resonance mass spectrometry

“…6 A detailed description of the sample preparation including information on employed protocols for LC and CE is available in the original research articles and reviews. 47,48 …”