Characterization of oxidation end product of plasma albumin 'in vivo'.
Anti-oxidants are paradoxically much lower in plasma than inside cells even blood is comparably exposed to the oxidative stress. 'In vitro' models suggest a critical role of albumin as substitutive anti-oxidant in plasma but no proof for this role is available 'in vivo.' Herein, we demonstrate by LC/MS/MS that plasma albumin undergoes massive oxidation in primary nephrotic syndrome, involving stable sulphonation SO3- of the free SH of Cys 34 with +48Da increase in exact mass of the protein (ESI-MS) and formation of a fast moving isoform in the pH range between 5 and 7. Physical-chemical experiments with DSC and fluorescence spectra indicate a thermal stabilization of the structure upon oxidation. This is the first demonstration of massive oxidation of albumin 'in vivo' that reflects a functional role of the protein. Free radicals should be implicated in the pathogenesis of proteinuria in human FSGS.
Musante
Luca
L
Laboratory on Pathophysiology of Uremia, G. Gaslini Children Hospital, Genoa, Italy.
Bruschi
Maurizio
M
Candiano
Giovanni
G
Petretto
Andrea
A
Dimasi
Nazzareno
N
Del Boccio
Piero
P
Urbani
Andrea
A
Rialdi
Giovanni
G
Ghiggeri
Gian Marco
GM
D000293:Adolescent; D000975:Antioxidants / Q000378:metabolism; D002152:Calorimetry, Differential Scanning; D002648:Child; D005260:Female; D005609:Free Radicals; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D009404:Nephrotic Syndrome / Q000097:blood / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism*; D012709:Serum Albumin / Q000032:analysis / Q000378:metabolism*; D013050:Spectrometry, Fluorescence; D021241:Spectrometry, Mass, Electrospray Ionization
D000975:Antioxidants; D005609:Free Radicals; D012709:Serum Albumin; D010100:Oxygen