effects. Previous studies from our laboratory and others show that exposure
of cells to HNE results in extensive protein modification [43,44].
Early studies to identify protein adducts relied largely on 2D-gel electrophoresis
coupled by Western blotting using antibodies specific for
HNE. This approach is useful for determining if a particular protein of
interest is adducted. However, the limitation of Western blotting is
that it does not allow the global analysis of potential electrophile
protein targets. Thus, a considerable obstacle in defining the role of
electrophile adduction in cell biology is the limitation in our ability to
monitor electrophile adduction in cellular systems. Identification and
characterization of electrophile protein targets in biological samples
is significantly complicated by the relatively low levels of adducts in
comparison to the large abundance of unmodified proteins. Global
analysis of electrophile adducts requires methodology to perform high
affinity capture of adducted proteins. Presently, the most effective
methods to study HNE susceptible protein involve a mass spectrometry
(MS)-based proteomic approach. Such methodologies not only allow
detection of protein targets at high resolution but also permit the
subsequent identification of specific amino acid residues modified by
lipid electrophiles.
The discovery of protein adducts has been greatly accelerated by the
use of alkynylated electrophiles thatmimic their native counterparts in
the adduction of target proteins [43]. Alkynylated electrophiles display
similar toxicity and react with target protein nucleophiles with similar
chemistry compared to non-alkynylated electrophiles. Alkynylated
electrophiles are also stable in cells and in vivo, which makes them