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Detection and characterization of variant and modified structures of proteins in blood and tissues by mass spectrometry
Author(s) -
Shimizu Akira,
Nakanishi Toyofumi,
Miyazaki Ayako
Publication year - 2006
Publication title -
mass spectrometry reviews
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.035
H-Index - 126
eISSN - 1098-2787
pISSN - 0277-7037
DOI - 10.1002/mas.20086
Subject(s) - chemistry , mass spectrometry , characterization (materials science) , chromatography , proteomics , mass spectrometry imaging , biochemistry , nanotechnology , materials science , gene
Some variant proteins cause diseases, and some diseases result in increases of proteins with abnormally modified structures. The detection, characterization, and estimation of the relative amounts of protein variants and abnormally modified proteins are important for clinical diagnosis and for elucidation of the mechanisms of the pathogenesis of diseases. Analysis of the covalent structures of proteins using matrix‐assisted laser desorption time‐of‐flight mass spectrometry (MALDI‐TOF‐MS) and liquid chromatography‐electrospray ionization MS (LC‐ESI‐MS), which had been developed by the early 1990s, have largely replaced analyses by conventional protein chemistry. Here, we review the detection and characterization of hemoglobin variants, HbA1c measurement, detection of carbohydrate‐deficient transferrin, and identification of variants of transthyretin (TTR) and Cu/Zn‐superoxide dismutase (SOD‐1) using soft ionization MS. We also propose the diagnostic application of the signals of modified forms of TTR, that is, S‐sulfonated TTR and S‐homocysteinyl TTR. The relative peak height ratio of the abnormal/normal components gives valuable information about the instability of variants and enables the detection of unstable Hb subunits or thalassemia heterozygotes. We found unique modified structures of TTR that suggested changes in amyloid fibrils. © 2006 Wiley Periodicals, Inc.