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In-Depth Information
expressed mitochondrial matrix and membrane proteins respec-
tively. To obtain a better insight of the modulation of TCA cycle in
response to fl ooding condition, metabolites were identifi ed using
capillary electrophoresis (CE)-MS. Flooding appears to cause con-
siderable impairment to the electron transport chain in the roots
and hypocotyls of soybean seedlings. Abundance of inner mem-
brane carrier proteins and proteins related to complexes III, IV, and
V of the electron transport chain were found to be reduced, while
proteins and metabolites related to TCA and gamma-amino butyr-
ate shunt were increased by fl ooding stress resulting high NADH
production. These responses of mitochondria to fl ooding stress
appear to be very similar with that of low oxygen stress, however
considerably different from their response to osmotic stress.
Peroxisomes, the ubiquitous cell organelles of eukaryotic cells, play
a major role in the breakdown of long chain fatty acids through
beta-oxidation. Although, peroxisomal proteins are encoded by
nuclear genes but they are fi nally targeted to peroxisomes due to
the presence of Peroxisome Targeting Signals (PTS). A majority of
the peroxisomal proteins are involved in a variety of oxidative met-
abolic reactions, however functions of a large number of proteins
remain unknown. Arai et al. [
43
] successfully characterized
peroxisomal proteins by a combination of 2-DE and peptide mass
fi ngerprinting using MALDI-TOF MS. Percoll density gradient
centrifugation followed by iodixanol density gradient centrifuga-
tion were used to isolate purifi ed peroxisomes from etiolated soy-
bean cotyledons. Identifi ed proteins are mainly enzymes involved
in fatty acid
4.4 Peroxisomal
Proteomics
-oxidation, glyoxylate cycle, photorespiratory glyco-
late metabolism, stress response and metabolite transport. Authors
demonstrated that the plant peroxisomes contain a short-chain
dehydrogenase/reductase family protein, enoyl-CoA hydratase/
isomerase family protein, 3-hydroxyacyl-CoA dehydrogenase-like
protein and a voltage-dependent anion-selective channel protein.
β
5
Conclusion
The scenario of soybean proteomics has started changing since
completion of soybean draft genome sequence. In spite of being a
recalcitrant plant species, protein extraction protocols have been
standardized to get optimized 2-DE results in terms of protein spot
number and spot intensity. Different tissue specifi c proteomic stud-
ies reveal that phenol and TCA/acetone based extraction protocol
are most suitable for soybean protein extraction. Construction of
detail quantitative soybean proteome reference maps not only
help functional genomic studies but also provide essential tool
for rapid identifi cation of soybean mutants/transgenic lines.
Identifi cations of low-abundance proteins become possible with the
development of sensitive stains and rapid technical advancement in
