Related Experiment Video
Updated: Aug 12, 2026
Matrix-assisted Laser Desorption/Ionization Time of Flight (MALDI-TOF) Mass Spectrometric Analysis of Intact Proteins Larger than 100 kDa
Published on: September 9, 2013
High resolution proteome analysis of cryoglobulins using Fourier transform-ion cyclotron resonance mass spectrometry
Eugen Damoc1, Nikolay Youhnovski, David Crettaz
1Laboratory of Analytical Chemistry, Department of Chemistry, University of Konstanz, 78457 Konstanz, Germany.
Insights
Researchers identified key protein components in cryoglobulins, which are cold-precipitable proteins linked to various diseases like hepatitis C. This analysis utilized advanced mass spectrometry to pinpoint specific immunoglobulin chains and associated proteins.
Area of Science:
- Biochemistry
- Immunology
- Analytical Chemistry
Background:
- Cryoglobulins are cold-precipitable immunoglobulins implicated in diverse diseases.
- The precise mechanisms and components of cryoprecipitation remain incompletely understood.
- Identifying cryoglobulin components is crucial for understanding associated pathologies.
Purpose of the Study:
- To identify the protein components within cryoglobulins using advanced analytical techniques.
- To elucidate the molecular composition of cryoglobulins, particularly in Type II cryoglobulinemia associated with Hepatitis C Virus (HCV).
Main Methods:
- Two-dimensional gel electrophoresis (2-DE) for protein separation.
- High-resolution Fourier transform-ion cyclotron resonance (FT-ICR) mass spectrometry for protein identification.
- Matrix-assisted laser desorption ionization (MALDI) coupled with FT-ICR MS for accurate mass determination and structural analysis.
Main Results:
- Identified immunoglobulin (Ig)M and IgG as major components in serum cryoprecipitate from an HCV patient.
- Characterized these immunoglobulins into mu- and gamma-heavy chains, kappa- and lambda-light chains, and J-chains.
- Directly identified complementarity determining regions (CDRs) of monoclonal IgM-RF variable region (V)L.
- Confirmed the presence of Spalpha, an IgM-associated protein, in the cryoprecipitate.
Conclusions:
- MALDI-FT-ICR MS provides high accuracy for identifying protein components in complex biological samples like cryoglobulins.
- Detailed characterization of cryoglobulin composition aids in understanding their role in diseases such as HCV.
- This methodology offers a powerful approach for future research into cryoglobulin-associated disorders.
Abstract:
Cryoglobulins are cold-precipitable serum immunoglobulins associated with a number of infectious, autoimmune and neoplastic disorders such as hepatitis C, Waldenström's macroglobulinemia, multiple myeloma, chronic lymphocytic leukemia, and rheumatoid arthritis. The mechanism(s) of cryoprecipitation has remained obscure hitherto, which has prompted recent intensive efforts on the identification of cryoglobulin components. In the present study, two-dimensional gel electrophoresis (2-DE) combined with high resolution Fourier transform-ion cyclotron resonance (FT-ICR) mass spectrometry has been applied as a powerful approach for the analysis of cryoglobulins. While FT-ICR mass spectrometry has been shown to enable the high resolution identification and structure analysis of biopolymers using both electrospray (ESI) and matrix-assisted laser desorption ionization (MALDI), the recently developed MALDI-FT-ICR source is shown here to provide high (sub-ppm) mass determination accuracy and isotopic fine structure as particular advantages in the identification of proteins. The main protein components in a serum cryoprecipitate from a patient with hepatitis C virus (HCV) infection and presenting type II cryogobulinemia are immunoglobulin (Ig)M and IgG which were identified by MALDI-FT-ICR MS analysis after separation by 2-DE as mu- and gamma-heavy chains, kappa- and lambda-light chains, and J-chains. Furthermore, complementarity determining regions CDR1 and CDR2 from monoclonal IgM-RF variable region (V)L were directly identified using accurate mass determinations by FT-ICR-MS. The presence of Spalpha was ascertained as an IgM-associated protein in the serum cryoprecipitate from a patient with HCV infection.
