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A mass spectrometric analysis of 4‐hydroxy‐2‐( E )‐nonenal modificationof cytochrome c
Author(s) -
Tang Xiaoxia,
Sayre Lawrence M.,
Tochtrop Gregory P.
Publication year - 2011
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/jms.1890
Subject(s) - chemistry , cytochrome c , adduct , cytochrome , mass spectrometry , biochemistry , proteolysis , lipid peroxidation , oxidative phosphorylation , mitochondrion , oxidative stress , tandem mass spectrometry , inner mitochondrial membrane , chromatography , organic chemistry , enzyme
Cytochrome c is a key mitochondrial respiratory protein that is particularly susceptible to modification during oxidative stress. The nature of this susceptibility is linked to the mitochondrial membrane being rich in esterified linoleic acid, which predisposes this organelle to the formation of lipid peroxidation products such as 4‐hydroxy‐2‐( E )‐nonenal (4‐HNE). To better understand the nature of cytochrome c modification by 4‐HNE, we initiated an in vitro study utilizing a combination of MALDI‐TOF mass spectrometry, LC‐ESI‐MS/MS and isotope labeling to monitor 4‐HNE modification of cytochrome c under various conditions. The overwhelming reaction observed is Michael addition by Lys side‐chains in addition to the modification of His 33. While the Lys‐4‐HNE adducts were generally observed to be reversible, the 4‐HNE‐His 33 was observed to be stable with half of the formed adduct surviving the denaturation and proteolysis protocols used to generate proteolytic peptides for LC–ESI‐MS/MS. Copyright © 2011 John Wiley & Sons, Ltd.